Author: HBP Neurorobotics Blog

Mouse modeling for robotics and neuroscience…

… or why we are building a zoo of artificial mice.

Neurorobotics is about connecting simulated brains to virtual and physical robot bodies. Differently from other approaches in robotics or machine learning, the focus is on high biological plausibility, i.e. a neurorobotic system is designed to capture and predict the quantitative behavior of its biological counterpart as closely as possible. However, what is exactly meant by “close” depends on the granularity of the brain model. Clearly, simple neural networks with only a few neurons can be studied on an equally simple robot. In case of the Braitenberg vehicle experiment on the Neurorobotics Platform, a mobile robot platform with four wheels and a camera is perfectly sufficient. By contrast, brain simulations that are comprised of millions of neurons require realistic body models to simulate and reproduce data from neuroscience as accurately as possible. In this context, standard robots are no longer a viable choice. Neurorobotics is therefore not only about connecting a robot body to a brain but also about the design, simulation, and construction of that body.

The brain models developed in the Human Brain Project are among the most complex and realistic ones ever built and therefore it is only logical that they require the most realistic body models ever built. But how does the perfect body model look like? The answer is both simple and tricky: Since most of the data in neuroscience is obtained from rodents, particularly mice, the perfect choice for the body model is to simulate a mouse body. The tricky part is to determine the level of detail that is necessary to provide meaningful embodiment for the brain models. We are therefore currently designing and building a zoo of different mouse models, each of which serves a specific purpose.

The maximum level of biological detail can only be achieved in simulation. For this reason, we are developing a virtual mouse body that not only looks like a real mouse but that also has the same biomechanical properties. Every bone of the skeleton was modeled individually based on bones of real mice. Combined with the musculoskeletal simulation that will soon be available in the Neurorobotics Platform, the skeleton will enable realistic biomechanical simulations.

Rendering of the completed mouse skeleton

The latest version of the virtual mouse got a soft skin that is fitted to the skeleton. Together with the recently added simulation of the fur, our mouse is almost indistinguishable from its biological colleagues!

Rendering of the mouse model with skin and fur

Unlike simulation, the real world imposes many constraints on the types of robots that can be built. However, having a physical counterpart to our virtual mouse is beneficial for many reasons. It not only enables direct interaction with the robot but is in particular also a first step to applying results from neurorobotics research in real-world applications. Our first prototype of the mouse robot was built with a focus on small size and biomimetic leg design for robust locomotion. Upcoming releases will not only feature improved mechanics but in particular also include more sensors. Follow our blog to see how our mouse is slowly growing up!

Completed initial prototype of the mouse robot

Many thanks to Matthias Clostermann, Eva Siehmann, and Peer Lucas for their contributions!

Florian Walter, Technical University of Munich
October 13, 2017


Simulating tendon driven robots

According to the concept of embodiment, a brain needs to be connected to a body interacting with the world for biological learning to happen, developing biomimetic robots is crucial to fully understand human intelligence. Here, a tendon driven approach can model muscle behavior in terms of flexibility, compliance and contractive force.

While this concept is clearly beneficial for research, it is very difficult to accurately model in simulation. In contrast to classical robots with motors applying torques in the joints, the simulation needs to apply forces  along wrapped ropes mimicking tendons and muscles. The artificial muscles developped in the Myorobotics [1] project include mechanical parts for flexiblity and force as well as electrical control in different operating modes as seen in Figure 1. To close the reality gap all physical properties need to be considered in modelling.


Figure 1: Myorobotics muscle unit (from [2])

We implemented a plugin for Gazebo that finally allows us to simulate the Myorobotics muscle setup. The plugin models tendon kinematics as well as mechanical and electrical properties of the technical actuator. The calculated forces derived from control commands can now be applied directly to a robot simulated in Gazebo. This brings it one step closer to being integrated into the NRP, allowing us to equip muscle units to arbitrary robot morphologies.

Ultimately, this will enable us to compare simulated biological muscles simulated by OpenSim to the technical muscle of Myorobotics modelled with this plugin. Eventually, this will help to build better biomimetic muscle units behaving just like their biological counterparts.



[2] C. Richter, S. Jentzsch, R. Hostettler, J. A. Garrido, E. Ros, A. Knoll, F. Röhrbein, P. van der Smagt, and J. Conradt, “Scalability in neural control”, IEEE ROBOTICS &AUTOMATIONMAGAZINE, vol. 1070, no. 9932/16, 2016.



Alexander Kuhn, Benedikt Feldotto (TU München)





Mid-Term Vision for HBP

This vision is for a seven-year time horizon: it is to be achieved by the end of the regular funding period of the HBP, i.e., by the time the HBP enters the status of a European Research Infrastructure. So, by 2023, we expect our current research in “Future Computing and Robotics” to have produced a number of unique, tangible results in the form of “products” and a number of ground breaking “base technologies and methods” that will significantly facilitate and accelerate future research in the European Infrastructure in a diverse range of fields.

In conjunction with future computing, HBP’s robotics research plays multiple, significant roles in the HBP:

  • (Closed Loop Studies): it links the real world with the “virtual world of simulation” by connecting physical sensors (e.g., cameras) in the real world to a simulated brain. This brain controls a body which, in turn, can impact and alter the real world environment. Robotics, therefore, provides the potential to perform realistic “closed-loop-studies”: perception – cognition – action. This will establish a whole new field of robot design: virtual prototyping of robots that can then be readily built as real machines and function like the simulated ones. This will not only speed up robot development by orders of magnitude, it will also dramatically improve the testing and verification of their behaviour within a wide variety of circumstances.
  • (Brain-Derived Products): it links brain research to information technology by using scientific results (e.g., data, and models of behaviour) obtained in brain research and refining it to a readiness level where it can be used by commercial companies and easily taken up and rapidly turned into new categories of products, e.g., using specialized neuromorphic hardware, also currently being developed by HBP. This will allow novel control technologies that achieve robustness and adaptivity far beyond todays algorithmic controls… and ones that actually rival biologic systems.
  • (Virtualised Brain Research): it links information technology to brain research by designing new tools for brain researchers, with which they can design experiments and then carry them out in simulation. For example, one can study a completely simulated animal’s navigation or sensorimotor skills as it operates in a completely simulated environment (e.g., a maze or a straight or sinusoidal vertical path), and the signals of the simulated brain will be recorded in real-time for immediate analysis. These same principles can be applied to humans and humanoid avatars, allowing bold and fruitful research on degenerative brain diseases, for example.

We envision that the unique integration of the above three paths will lead to widespread mutually beneficial fertilization and research acceleration through the two-way inspiration of the involved disciplines. The vehicle for bi-directional translation (brain science « robotics) is the HBP’s neurorobotics platform.

At this point, we can see the following vision  taking shape: we have taken the first steps towards the design of a virtual mouse. This animal, which only exists in a computer, has eyes, whiskers, skin, a brain, and a body with bones and muscles that function exactly like its natural counterpart. Clearly, all of these elements are still far from being perfect, i.e., from exhibiting behaviour and function corresponding to the original creature. However, the more brain scientists learn about these functions and the more data become available, the more we can integrate said results into the virtual mouse, and the faster we can improve the “mouse fidelity”. In parallel, we will apply the same principles to the simulation of human embodiment. The possibilities are endless.

Using the virtual mouse (or humans, or any other animals) in the future, brain scientists can not only copy traditional design experiments into the computer and study the results immediately, they can also modify the mouse any way they want, e.g., introduce lesions into the brain or cut muscles and study the impact it has. Moreover, they can place as many electrodes or other sensors in the body as they want. But perhaps the most astounding benefits of these new possibilities are that scientists can perform experiments that are very, complex – if not impossible to perform in the real world. This includes very long-term studies with permanent recordings (and these can be done 10,000 times faster than in real-time!), animal swarms with parallel recordings, and plasticity and learning effects over many years.

On the technology side, we can envision a number of brain-derived base technologies that result from our work. One straightforward example is robot-based prostheses that have myo-electric interfaces and which can not only be developed in simulation, but which can be tailor-made or personalized to the properties of one specific person – because every single aspect can be simulated. This is a rather simple example; the disruptive products will most likely involve a complex artificial brain running on neuromorphic hardware and capable of super-fast learning, which, for the first time, would make highly intelligent household robots possible that can adapt their behaviour to various tasks.

Substantial progress towards both a comprehensive understanding of the brain and technologies that are derived from the brain’s working principles can only be made by advancing theory and methodology at the system level. While the fields of artificial intelligence and machine learning in particular have recently gained unprecedented momentum that is primarily driven by the success of big data and deep neural networks, the resulting tools, models, and methods are still highly domain-specific. With the ubiquitous availability of cheap storage, massive processing power, and large-scale datasets, the actual challenge no longer lies in the design of a system that performs a specific task, but in the integration of the wealth of different narrow-scoped models from machine learning and neuroscience channelled into a coherent cognitive model. The platform infrastructure of HBP enables the design and implementation of such a model by integrating different tools, methods and theories in a common research environment. For the very first time, different brain theories, neural network architectures and learning algorithms can be directly comparable to both each other and to experimental ground truth. In this context, neurorobotics serves as a central “workbench” for the study of integrated cognitive models in real-world tasks and as a prototyping tool that enables the seamless transfer of these models into new products and services.

To achieve these goals, we need to reinforce the “input side”, i.e., brain scientists need to talk to roboticists much more intensively than they have done up to now. Then, really new concepts can emerge. One particularly attractive concept could be the automatic generation of models from data: data driven model generation. This would make it possible to use every new data collection to improve the virtual models with a minimum of human intervention and hence keep the virtual robot permanently and synergetically coupled to developments in brain science. Of central importance is the permanent adjustment and calibration of these data models with the corresponding cognitive brain system, which in itself is a complex and long-term endeavour. This goal can only be achieved on the basis of a very close interaction between theorists, data/computer scientists and engineers – and as such, could be a perfect example of a synergistic transdisciplinary cooperation that can only be performed in a European Research Infrastructure.





Functional components for control and behavioural models

Gaze stabilization experiment

In this work, we focused on reflexes used by humans for gaze stabilization. A model of gaze stabilization, based on the coordination of the vestibulo-collic reflex (VCR) and vestibulo-ocular reflex (VOR) has been designed and implemented on humanoid robots. The model, inspired on neuroscientific cerebellar theories, is provided with learning and adaptation capabilities based on internal models.

In a first phase, we designed experiments to assess the model’s response to disturbances, validating the model both with the NRP and with a real humanoid robot (SABIAN). In this phase, we mounted the SABIAN head on an oscillating platform (shown below) able to rotate along the pitch axis, in order to produce a disturbance.

The oscillating platform. In (a) the SABIAN head mounted on the platform, with its inertial reference frame is shown. The transmission of motion from the DC motor to the oscillating platform is depicted in (b).

In a second phase, we carried out experiments for testing the gaze stabilization capability of the model, during a locomotion task. We gathered human data of torso displacement while walking and running. The data has been used to animate a virtual iCub while the gaze stabilization model was active.

Balancing experiment

Using the same principles of the gaze stabilization experiment, we carried out a balancing experiment for a simulated iCub. In this experiment, the simulated iCub is holding up a red tray with a green ball on top. The goal of the experiment is to control the robot’s roll and pitch joints for the wrist, in order to keep the ball in the center of the tray. The control model for the wrist joints is provided with learning and adaptation capabilities based on internal models.

Visual segmentation experiment

A cortical model for visual segmentation (Laminart) has been built with the aim of integrating it in the neurorobotics platform. The goal is to see how the model behaves in a realistic visual environment. A second goal is to connect it to another model for the retina.
The model consists of a biologically plausible network containing hundreds of thousands of neurons and several millions connections embedded in about 50 cortical layers. It is built functionnaly in order to link objects that are likely to group together with illusory contours, and to segment disctinct perceptual groups in separate segmentation layers.
Up to now, the Laminart model has been successfully integrated in the NRP and first expriments are being built to check the behaviour of the model and discover what has to be added to it to ensure it can coherently segment objects from each other in a realistic environment. Besides, the Laminart model is almost connected to the retina model.
In the future, the model will be connected to other models for saliency detection, learning, predictive coding, decision making, on the NRP, to create a closed loop experiment. It will also take into account some experimental data about texture segmentation and contour integration.

Visual perception experiment

In this work, we evaluated the construction of neural models for visual perception. The validation scenario chosen for the models is an end-to-end controller capable of lane following for an self-driving vehicle. We developed a visual encoder from camera images to spikes inspired by the silicon retina (i.e., the DVS Dynamic Vision Sensor). The veichle controller embeds a wheel decoder based on a virtual agonist antagonist muscle model.


Grasping experiment

During the first 12 month of SGA1, we investigated methods for representing and executing grasping motions with spiking neural networks that can be simulated in the NEST simulator and therefore, the Neurorobotics Platform. For grasping in particular, humans can remember motions and modify them while executing based on the shape and the interaction with objects. We developed a spiking neural network with a biologically inspired architecture to perform different grasping motions, that first learns with plasticity from human demonstration in simulation and then is used to control a humanoid robotic hand. The network is made with two types of associative networks trained independently: One represents single fingers and learns joint synergies as motion primitives; and another represents the hand and coordinates multiple finger networks to execute a specific grasp. Both receive the joint states as proprioception using population encoding, and the finger networks also receives tactile feedback to inhibit the output neurons and stop the motion if a contact with an object is detected.



Multimodal sensory representation for invariant object recognition

This functional component integrates multisensory information -namely tactile, visual and auditory- to form an object representation. Although we firstly target invariant object recognition problem using the only visual information, the component is capable of combining other sensory modalities. The model is based on computational phases of the Hierarchical Temporal Memory which is inspired by operating principles of the mammalian neocortex. The model was adapted and modified to extract a multimodal sensory representation of an object. The representation can be interpreted as a cortical representation of perceived inputs. To test the model, we perform object recognition in COIL-20 and COIL-100 datasets in which consist of 20 and 100 different objects (see Figure 1). In details, each object rotated 5 degrees on a turntable and object image was captured by the camera (see Figure2). In addition to image acquisition steps, a number post-processing procedures such as background elimination and size normalization were performed on the images.


Figure 1 Selected images from different categories.


Figure 2 A duck object under various rotational transformations.

To obtain object representations, the standard image processing algorithms were performed to binarize and downsize available images in datasets. Then, the model was fed with the processed image data to generate sparsely distributed representation of the perceived images. A sample processed image and cortical representation of the same visual pattern are illustrated in Figure 3 and Figure 4, respectively. Note that, the representation of an object with different sensory inputs can be achieved by same procedure and concatenating the obtained representations for each modality.

Figure 3 A processed visual pattern.                            Figure 4 Cortical representation of a visual pattern

After obtaining representation for all images, we perform recognition operations by grouping the datasets into two categories which are memory representation (or training set) and unseen object patterns (or test set). The representation similarity metric defined as the number of same active cortical columns (the same active bits in the same location) between existing and unseen patterns. The recognition accuracies are shown in Table below. and were derived via splitting training and testing dataset by 10% to 90% and each time incremented by 10.

Training percent






























The obtained results indicate that the modal performs well with single modality. Our ongoing studies focus on integrating multiple sensory information (e.g. tactile) to represent multimodal representation to achieve a grasping task.

Integrating Nengo into the NRP?

On 11th March we had the honor of welcoming Terrence Stewart from the University of Waterloo ( at the Technical University of Munich. During these two days, he first gave a fascinating presentation on Nengo and neural engineering in general.
This was followed by extensive discussions with our developers to investigate a possible integration of Nengo into our platform after it had been installed on his laptop. To this extent, we discussed what overlaps already exist and identified missing parts to make this integration happen.
This yields the opportunity for our NRP to offer additional spiking neuron simulators aside from NEST.
This collaboration would be benefitial for both sides, with us offereing a platform to interface Nengo with Roboy or other muscle based simulations.


New frontiers Article Explains the Technology Powering the HBP Neurorobotics Platform


After our recent Science Supplement article on Neurorobotics in the Human Brain Project, our paper “Connecting artificial brains to robots in a comprehensive simulation framework: the Neurorobotics Platform” now got accepted for publication by frontiers in Neurorobotics. Which of the papers should you read? Definitely both! The Science Supplement article states the key concepts of neurorobotics and outlines how they are reflected in the HBP Neurorobotics Workflow. The new frontiers paper explains how this workflow is actually implemented in the Neurorobotics Platform:

“Combined efforts in the fields of neuroscience, computer science and biology allowed to design biologically realistic models of the brain based on spiking neural networks. For a proper validation of these models, an embodiment in a dynamic and rich sensory environment, where the model is exposed to a realistic sensory-motor task, is needed. Due to the complexity of these brain models that, at the current stage, cannot deal with real-time constraints, it is not possible to embed them into a real world task. Rather, the embodiment has to be simulated as well. While adequate tools exist to simulate either complex neural networks or robots and their environments, there is so far no tool that allows to easily establish a communication between brain and body models. The Neurorobotics Platform is a new web-based environment that aims to filling this gap by offering scientists and technology developers a software infrastructure allowing them to connect brain models to detailed simulations of robot bodies and environments and to use the resulting neurorobotic systems for in-silico experimentation.

In order to simplify the workflow and reduce the level of the required programming skills, the platform provides editors for the specification of experimental sequences and conditions, environments, robots, and brain-body connectors. In addition to that, a variety of existing robots and environments are provided. This work presents the architecture of the first release of the Neurorobotics Platform developed in subproject 10 “Neurorobotics” of the Human Brain Project (HBP). At the current state, the Neurorobotics Platform allows researchers to design and run basic experiments in neurorobotics using simulated robots and simulated environments linked to simplified versions of brain models. We illustrate the capabilities of the platform with three example experiments: a Braitenberg task implemented on a mobile robot, a sensory-motor learning task based on a robotic controller and a visual tracking embedding a retina model on the iCub humanoid robot. These use-cases allow to assess the applicability of the Neurorobotics Platform for robotic tasks as well as in neuroscientific experiments.”

Can’t wait to start reading the paper? A preprint is availalble for free open access download on frontiers.

Publication in a Supplement to Science on Brain-Inspired Intelligent Robotics

The article “Neurorobotics: A strategic pillar of the Human Brain Project” was released in a Science Supplement on “Brain-inspired intelligent robotics: The intersection of robotics and neuroscience”, explaining the importance of our subproject and its research.


To give you an overview, you can find the first section below:

“Neurorobotics is an emerging science that studies the interaction of brain, body, and environment in closed perception–action loops where a robot’s actions affect its future sensory input. At the core of this field are robots controlled by simulated nervous systems that model the structure and function of biological brains at varying levels of detail (1). In a typical neurorobotics experiment, a robot or agent will perceive its current environment through a set of sensors that will transmit their signals to a simulated brain. The brain model may then produce signals that will cause the robot to move, thereby changing the agent’s perception of the environment. Observing how the robot then interacts with its environment and how the robot’s actions influence its future sensory input allows scientists to study how brain and body have to work together to produce the appropriate response to a given stimulus. Thus, neurorobotics links robotics and neuroscience, enabling a seamless exchange of knowledge between these two disciplines. Here, we provide an introduction to neurorobotics and report on the current state of development of the European Union–funded Human Brain Project’s (HBP’s) Neurorobotics Platform (2, 3). HBP is Europe’s biggest project in information communication technologies (ICT) to date ( and is one of two large-scale, long-term flagship research initiatives selected by the European Commission to promote disruptive scientific advance in future key technologies. It will have a duration of 10 years and deliver six open ICT platforms for future research in neuroscience, medicine, and computing, aimed at unifying the understanding of the human brain and translating this knowledge into commercial products.”

Read the entire paper here on page 25:

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