Trajectory Learning for Stable Bipedal Walking Robots using Sequential Networks

Author(s):  
Gaurav Kumar Yadav ◽  
Shruti Jaiswal ◽  
G.C. Nandi
Author(s):  
Sergei Savin

In this chapter, the problem of trajectory generation for bipedal walking robots is considered. A number of modern techniques are discussed, and their limitations are shown. The chapter focuses on zero-moment point methods for trajectory generation, where the desired trajectory of that point can be used to allow the robot to keep vertical stability if followed, and presents an instrument to calculate the desired trajectory for the center of mass for the robot. The chapter presents an algorithm based on quadratic programming, with an introduction of a slack variable to make the problem feasible and a change of variables to improve the numeric properties of the resulting optimization problem. Modern optimization tools allow one to solve such problems in real time, making it a viable solution for trajectory planning for the walking robots. The chapter shows a few results from the numerical simulation made for the algorithm, demonstrating its properties.


2021 ◽  
Vol 15 ◽  
Author(s):  
Dai Owaki ◽  
Shun-ya Horikiri ◽  
Jun Nishii ◽  
Akio Ishiguro

Despite the appealing concept of central pattern generator (CPG)-based control for bipedal walking robots, there is currently no systematic methodology for designing a CPG-based controller. To remedy this oversight, we attempted to apply the Tegotae approach, a Japanese concept describing how well a perceived reaction, i.e., sensory information, matches an expectation, i.e., an intended motor command, in designing localised controllers in the CPG-based bipedal walking model. To this end, we developed a Tegotae function that quantifies the Tegotae concept. This function allowed incorporating decentralised controllers into the proposed bipedal walking model systematically. We designed a two-dimensional bipedal walking model using Tegotae functions and subsequently implemented it in simulations to validate the proposed design scheme. We found that our model can walk on both flat and uneven terrains and confirmed that the application of the Tegotae functions in all joint controllers results in excellent adaptability to environmental changes.


Author(s):  
Sergei Savin

In this chapter, the problem of controlling bipedal walking robots with integrated elastic elements is considered. A survey of the existing control methods developed for walking robots is given, and their applicability to the task of controlling the robots with elastic elements is analyzed. The focus of the chapter lies with the feedback controller design. The chapter studies the influence that the elastic elements modelled as a spring-damper system have on the behavior of the control system. The influence of the spring-damper parameters and the inertial parameters of the actuator gear box and the motor shaft on the generated control laws and the resulting peak torques are discussed. The changes in these effects associated with motor torque saturation and sensors nonlinearities are studied. It is shown that the introduction of torque saturation changes the way the elastic drive parameters affect the resulting behavior of the control system. The ways to use obtained results in practice are discussed.


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