Posture stabilization of Skid Steer Wheeled Mobile Robots

Bulletin of the Polish Academy of Sciences Technical Sciences

Cholewinski

2016

Abstract. In the paper implementation of the factitious force concept for a controlling complex mobile manipulator has been presented. As the nonholonomic constraint only lack of longitudinal slippage of wheels has been chosen -in skid-steering platforms lateral slippage is necessary to change orientation of such a platform. From a control theory point of view such a system is dynamically underactuated. As a solution to a underactuation problem a method of factitious force has been proposed. This method assumes extension on the dynamics level, in the form of an additional control inputs uv, which values are equal to zero equivalently. For a mobile manipulator, consisting of platform REX and 5R robotic onboard arm, a cascaded control law has been proposed. A simulation study was conducted for a mathematical model of a considered object with real values of physical parameters, i.e. lengths, masses, inertia moments etc. obtained from the 3D model. Results obtained in simulations have shown a proper action of the control system and convergence of tracking errors, occurring in a platform and in joints of a manipulator, to zero.

“…They have used the tunable dynamic oscillator to get globally uniformly bounded stability of the proposed control algorithm. The same idea can be found in [6] and [7].…”

Section: Introductionmentioning

confidence: 76%

Implementation of factitious force method for control of 5R manipulator with skid-steering platform REX

Bulletin of the Polish Academy of Sciences Technical Sciences

Cholewinski

2016

“…They have used tunable dynamic oscillator to get globally uniformly bounded stability of proposed control algorithm. The same idea can be found in [12] and [7].…”

Section: Introductionmentioning

confidence: 76%

Control of Underactuated Skid Steering Mobile Platforms Based on Extended Factitious Force Concept

Domski

Roszkowska

2016

J Intell Robot Syst

In the paper new control method of skid steering mobile platforms has been presented. Such platforms are robotic objects with deficit of control inputs in dynamic model, i.e. they are dynamically under-actuated. To compensate lack of controls, it has been assumed that there are additional factitious inputs to dynamics (so-called factitious forces), which preserve possibility to control dynamical model of skid steering mobile platform, expressed in auxiliary velocities. Factitious inputs do not exist in reality therefore it was assumed that they are equal to zero equivalently. Signals calculated from implicit functions defining factitious forces make possible to approximate slipping effects and they can be taken into account by construction of control law.

“…Authors have shown that skidsteering mobile platform is an underactuated system on dynamic level with non-stationary velocity constraint (nonstationary kinematics). The same idea can be found in [14] and [9]. This paper focuses on the second possible approach to solve the under-actuation problem -it is extended factitious force method where the first announcement about this method, for single factitious force, can be found in [11].…”

Section: Underactuated Dynamicsmentioning

confidence: 99%

Extended Factitious Force Approach for Control of a Mobile Manipulator Moving on Unknown Terrain

Domski

Kaczmarek

2018

J Intell Robot Syst

In the paper a new control algorithm for mobile manipulators with skid-steering platform, moving on unknown terrain, has been introduced. The mobile manipulator consists of a skid-steering mobile platform and a 2R rigid manipulating arm mounted on the platform. Due to under-actuation of such mobile platforms, the concept of factitious force (which does not exist in reality and is assumed to be always 0) has been utilised. Presented control law, in adaptive and robust version, guarantees asymptotically fast convergence of tracking errors to 0, which has been proved in the article. Simulations, which have been conducted for object of considerations, confirm that the developed control law works properly even in terrain which parameters are unknown and piece-wise constant.