Simulation is a key technology in robotics as it enables the generation of environmental data and testing scenarios for development and maintenance purposes. However, simulations are an imperfect representation of the real-world and the so-called sim-to-real gap between simulation and reality hinders the deployment of virtual developed solutions without additional effort. Modeling complex systems like highly dynamic and holonomic mobile robots presents additional complexities in simulation. This paper addresses these challenges through a case study on creating a model for a highly dynamic logistics robot. The study considers the modeling of the entire system down to creating suitable colliders for the rollers of a Mecanum wheel. Additionally, the impact of significant physics parameters is presented. To bridge the sim-to-real gap, a pipeline is developed that utilizes a Motion Capture system to compare the behavior of a real robot with its simulated counterpart across various motions. By leveraging expert knowledge gained from the real-world data, the simulation model is manually tuned to replicate complex system behaviors, such as sliding effects.

In this paper, we present a new locomotion control method for soft robot snakes. Inspired by biological snakes, our control architecture is composed of two key modules: A reinforcement learning (RL) module for achieving adaptive goal-tracking behaviors with changing goals, and a central pattern generator (CPG) system with Matsuoka oscillators for generating stable and diverse locomotion patterns. The two modules are interconnected into a closed-loop system: The RL module, analogizing the locomotion region located in the midbrain of vertebrate animals, regulates the input to the CPG system given state feedback from the robot. The output of the CPG system is then translated into pressure inputs to pneumatic actuators of the soft snake robot. Based on the fact that the oscillation frequency and wave amplitude of the Matsuoka oscillator can be independently controlled under different time scales, we further adapt the option-critic framework to improve the learning performance measured by optimality and data efficiency. The performance of the proposed controller is experimentally validated with both simulated and real soft snake robots.

In this work we present a framework that is capable of accurately representing soft robotic actuators in a multiphysics environment in real-time. We propose a constraint-based dynamics model of a 1-dimensional pneumatic soft actuator that accounts for internal pressure forces, as well as the effect of actuator latency and damping under inflation and deflation and demonstrate its accuracy a full soft robotic snake with the composition of multiple 1D actuators. We verify our model's accuracy in static deformation and dynamic locomotion open-loop control experiments. To achieve real-time performance we leverage the parallel computation power of GPUs to allow interactive control and feedback.