Design of Control System for Quadruped Robot (4-Legged Robot)

The project outcome is to design a control system for quadruped robot (4-legged robot). Early 2007, a quadruped robot was built by an UTP graduate; Mr. Tnay Chiat Siang (Matric No. 6114). The quadruped robot is well constructed in mechanicalwise; however, it has never been able to move as there is no motor driver and control system being developed for it. Therefore, the author has decided to come in on Mr. Tnay Chiat Siang’s quadruped project and continue his work to develop a control system which will eventually drive the quadruped robot to perform crawling gait on flat and horizontal ground. The control system of quadruped involves gait control, stability control and motor control. This project is split to three phases. The timeline of each phase is that phase 1 is carried out at semester FYP 1 while phase 2 begins during the year-end semester break. Phase 3 is commenced during FYP 2. The work aspect of phase 1 is on schematic design and crawling gait planning of quadruped. A preliminary simulation is used to demonstrate the planned crawling gait. The focus of phase 2 is more on learning how to manipulate PIC microcontroller and servomotors. At last, phase 3 is the prototype fabricating and testing stage with the presence of servomotors and circuit board. At the end of project, the quadruped prototype is meant to perform forward crawling gait on flat and horizontal ground

Design of Control System for Quadruped Robot (4-Legged Robot)

The project outcome is to design a control system for quadruped robot (4-legged robot). Early 2007, a quadruped robot was built by an UTP graduate; Mr. Tnay Chiat Siang (Matric No. 6114). The quadruped robot is well constructed in mechanicalwise; however, it has never been able to move as there is no motor driver and control system being developed for it. Therefore, the author has decided to come in on Mr. Tnay Chiat Siang’s quadruped project and continue his work to develop a control system which will eventually drive the quadruped robot to perform crawling gait on flat and horizontal ground. The control system of quadruped involves gait control, stability control and motor control. This project is split to three phases. The timeline of each phase is that phase 1 is carried out at semester FYP 1 while phase 2 begins during the year-end semester break. Phase 3 is commenced during FYP 2. The work aspect of phase 1 is on schematic design and crawling gait planning of quadruped. A preliminary simulation is used to demonstrate the planned crawling gait. The focus of phase 2 is more on learning how to manipulate PIC microcontroller and servomotors. At last, phase 3 is the prototype fabricating and testing stage with the presence of servomotors and circuit board. At the end of project, the quadruped prototype is meant to perform forward crawling gait on flat and horizontal ground

Design of Control System for Quadruped Robot (4-Legged Robot)

The project outcome is to design a control system for quadruped robot (4-legged robot). Early 2007, a quadruped robot was built by an UTP graduate; Mr. Tnay Chiat Siang (Matric No. 6114). The quadruped robot is well constructed in mechanicalwise; however, it has never been able to move as there is no motor driver and control system being developed for it. Therefore, the author has decided to come in on Mr. Tnay Chiat Siang's quadruped project and continue his work to develop a control system which will eventually drive the quadruped robot to perform crawling gait on flat and horizontal ground. The control system of quadruped involves gait control, stability control and motor control. This project is split to three phases. The timeline of each phase is that phase 1 is carried out at semester FYP 1 while phase 2 begins during the year-end semester break. Phase 3 is commenced during FYP 2. The work aspect of phase 1 is on schematic design and crawling gait planning of quadruped. A preliminary simulation is used to demonstrate the planned crawling gait. The focus of phase 2 is more on learning how to manipulate PIC microcontroller and servomotors. At last, phase 3 is the prototype fabricating and testing stage with the presence of servomotors and circuit board. At the end of project, the quadruped prototype is meant to perform forward crawling gait on flat and horizontal ground

Effects of Initial Stance of Quadruped Trotting on Walking Stability

It is very important for quadruped walking machine to keep its stability in high speed walking. It has been indicated that moment around the supporting diagonal line of quadruped in trotting gait largely influences walking stability. In this paper, moment around the supporting diagonal line of quadruped in trotting gait is modeled and its effects on body attitude are analyzed. The degree of influence varies with different initial stances of quadruped and we get the optimal initial stance of quadruped in trotting gait with maximal walking stability. Simulation results are presented. Keywords: quadruped, trotting, attitude, walking stability

Dynamically Stable 3D Quadrupedal Walking with Multi-Domain Hybrid System Models and Virtual Constraint Controllers

Hybrid systems theory has become a powerful approach for designing feedback controllers that achieve dynamically stable bipedal locomotion, both formally and in practice. This paper presents an analytical framework 1) to address multi-domain hybrid models of quadruped robots with high degrees of freedom, and 2) to systematically design nonlinear controllers that asymptotically stabilize periodic orbits of these sophisticated models. A family of parameterized virtual constraint controllers is proposed for continuous-time domains of quadruped locomotion to regulate holonomic and nonholonomic outputs. The properties of the Poincare return map for the full-order and closed-loop hybrid system are studied to investigate the asymptotic stabilization problem of dynamic gaits. An iterative optimization algorithm involving linear and bilinear matrix inequalities is then employed to choose stabilizing virtual constraint parameters. The paper numerically evaluates the analytical results on a simulation model of an advanced 3D quadruped robot, called GR Vision 60, with 36 state variables and 12 control inputs. An optimal amble gait of the robot is designed utilizing the FROST toolkit. The power of the analytical framework is finally illustrated through designing a set of stabilizing virtual constraint controllers with 180 controller parameters.Comment: American Control Conference 201

Autonomous Locomotion Mode Transition Simulation of a Track-legged Quadruped Robot Step Negotiation

Multi-modal locomotion (e.g. terrestrial, aerial, and aquatic) is gaining increasing interest in robotics research as it improves the robots environmental adaptability, locomotion versatility, and operational flexibility. Within the terrestrial multiple locomotion robots, the advantage of hybrid robots stems from their multiple (two or more) locomotion modes, among which robots can select from depending on the encountering terrain conditions. However, there are many challenges in improving the autonomy of the locomotion mode transition between their multiple locomotion modes. This work proposed a method to realize an autonomous locomotion mode transition of a track-legged quadruped robot steps negotiation. The autonomy of the decision-making process was realized by the proposed criterion to comparing energy performances of the rolling and walking locomotion modes. Two climbing gaits were proposed to achieve smooth steps negotiation behaviours for energy evaluation purposes. Simulations showed autonomous locomotion mode transitions were realized for negotiations of steps with different height. The proposed method is generic enough to be utilized to other hybrid robots after some pre-studies of their locomotion energy performances

Body randomization reduces the sim-to-real gap for compliant quadruped locomotion

Designing controllers for compliant, underactuated robots is challenging and usually requires a learning procedure. Learning robotic control in simulated environments can speed up the process whilst lowering risk of physical damage. Since perfect simulations are unfeasible, several techniques are used to improve transfer to the real world. Here, we investigate the impact of randomizing body parameters during learning of CPG controllers in simulation. The controllers are evaluated on our physical quadruped robot. We find that body randomization in simulation increases chances of finding gaits that function well on the real robot

First Steps Towards Full Model Based Motion Planning and Control of Quadrupeds: A Hybrid Zero Dynamics Approach

The hybrid zero dynamics (HZD) approach has become a powerful tool for the gait planning and control of bipedal robots. This paper aims to extend the HZD methods to address walking, ambling and trotting behaviors on a quadrupedal robot. We present a framework that systematically generates a wide range of optimal trajectories and then provably stabilizes them for the full-order, nonlinear and hybrid dynamical models of quadrupedal locomotion. The gait planning is addressed through a scalable nonlinear programming using direct collocation and HZD. The controller synthesis for the exponential stability is then achieved through the Poincaré sections analysis. In particular, we employ an iterative optimization algorithm involving linear and bilinear matrix inequalities (LMIs and BMIs) to design HZD-based controllers that guarantee the exponential stability of the fixed points for the Poincaré return map. The power of the framework is demonstrated through gait generation and HZD-based controller synthesis for an advanced quadruped robot, —Vision 60, with 36 state variables and 12 control inputs. The numerical simulations as well as real world experiments confirm the validity of the proposed framework