Real-time capable model inversion of underactuated multibody systems using servo-constraints

使用伺服约束对欠驱动多体系统进行实时模型反演

• 批准号: 396289190
• 负责人: Professor Dr.-Ing. Robert Seifried
• 金额: --
• 依托单位: Institut für Mechanik und Meerestechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/396289190?language=en
• 关键词: Real; time; capable; model; inversion

Underactuated multibody systems are mechanical systems which haves less control inputs than degrees of freedom. An inverse model provides for a given output trajectory the associated control inputs and the trajectories of all coordinates of the system. Inverse models are used as feedforward control in combination with feedback control for trajectory tracking of multibody systems. The aim of the proposed project is the development of real-time capable inverse models of underactuated multibody systems. Thereby the servo-constraint approach is used, which originates in multibody dynamics. This is a systematic numerical approach which is applicable to a wide range of systems. The mathematical model of multibody systems consists of the equation of motion with control inputs and the defined output equations. For the inverse model additional servo-constraints for the output are defined, such that these follow predefined trajectories. The systems considered in this project are either differentially flat systems or systems with stable internal dynamics. The biggest challenge in this project is the design and real-time solution of inverse models, which have a higher differential index and an internal dynamics. At the end of this project such systems should be treated, especially with several inputs and outputs. In the scope of this project it should also be investigated if the choice of coordinates, i.e minimal coordinates or redundant coordinates, has an influence on the solution and efficiency of the inverse model. Currently this is an open question since due to the servo-constraints always a differential algebraic equation arises. Using the simple example of a crane it has been already demonstrated that here redundant coordinates are not necessarily less efficient than using generalized coordinates. This will be especially interesting for more complex three-dimensional systems. Under given time step constraints the limits of real-time capable model inversion should be tested. Hereby for systems with internal dynamics it has to be considered that their characteristic might be fundamental faster than the forward dynamics. Finally, using basic experiments the accuracy of inverse models should be tested. Therefore a modular testbed will be set-up, which allows the testing of 4 structurally different systems.

多体系统是机械系统，其控制输入比自由度少。逆模型为给定的输出轨迹提供了相关的控制输入和系统所有坐标的轨迹。逆模型与反馈控制组合用作馈电控制，用于多体系统的轨迹跟踪。拟议项目的目的是开发不足的多体系统的实时逆模型。因此，使用了伺服构成方法，该方法起源于多体动力学。这是一种系统的数值方法，适用于广泛的系统。多体系统的数学模型由具有控制输入和定义的输出方程的运动方程组成。对于反向模型，定义了输出的其他伺服构造，以便这些遵循预定义的轨迹。该项目中考虑的系统是差异化的系统，或具有稳定内部动力学的系统。该项目中最大的挑战是逆模型的设计和实时解决方案，它们具有更高的差异索引和内部动力学。在该项目结束时，应该对此系统进行处理，尤其是使用多个输入和输出。在该项目的范围内，如果选择坐标（即最小坐标或冗余坐标）对逆模型的解决方案和效率有影响，则还应研究。目前，这是一个悬而未决的问题，因为由于伺服构成始终会出现差异代数方程。使用起重机的简单示例，已经证明，这里的冗余坐标不一定比使用广义坐标效率较低。对于更复杂的三维系统，这将特别有趣。在给定的时间步骤约束下，应测试实时模型反转的限制。特此，对于具有内部动力学的系统，必须认为它们的特征可能比向前动态更快。最后，使用基本实验应测试反向模型的精度。 因此，将设置模块化测试床，该测试床允许测试4个结构上不同的系统。