| In space robotics systems, contact often occurs between a robotic manipulator and other bodies and will affect the performance of the manipulator's control and mechanical systems. In order to check whether a task can be performed successfully, and to predict potential dangers and problems, an accurate and efficient contact model for space robotics systems is highly desirable.;Based on elasticity theory and contact type classification, a uniform load-deformation relationship is obtained through the introduction of a shape coefficient to consider the effect of the shape of contact region. Moreover, a case coefficient is used to account for different contact types: point, line and face contact. Use of a shape coefficient and a case efficient leads to a comprehensive compliant contact model for polyhedral contacting objects, which has a solid basis in elasticity theory. Compared to existing contact models, this new model has two distinguishing characteristics: general applicability to a wide diversity of object shapes and contact types, and a careful consideration of the detailed contact geometry in order to improve the model's accuracy.;An interference geometry algorithm, targeted to calculate all the geometric parameters needed by the comprehensive compliant contact model, is developed. A theoretical basis and two algorithms for the calculation of the overlap polyhedron of two contacting objects are investigated. Two methods to obtain the contact area and contact normal are discussed: an area-weighted normal method and a least-squares fitting plane method. A definition of penetration distance and two methods to calculate the application point of the interbody contact force are proposed.;Existing models for energy dissipation during contact are surveyed and classified into two groups: impacts having small permanent deformation or material damping, and those having severe permanent deformation. A damping model, which is well suited to the proposed compliant contact model, is proposed to account for energy dissipation during impact.;The research in this thesis focuses on investigating a geometry-based contact force model with high accuracy and general applicability for space robotics systems. This work is comprised of three parts: compliant contact force modeling including damping, interference geometry algorithm, and model validation.;The model validations are performed in three ways: validation against available analytical results, validation against FEA (Finite Element Analysis) results, and validation against experimental results.;The integration of the proposed contact model and interference geometry algorithm into our industrial collaborator's robotic system simulation package is discussed. Test examples are presented using the integrated robotic system simulation package. |
