轮式双足机器人的设计与控制

随着技术的成熟，移动机器人已逐渐应用于各个行业，发挥着越来越重要的作用。但人类生活场景复杂多变，主流的轮式机器人只能在平坦路面运行，难以适应崎岖复杂地形，而纯足式机器人虽然可以适应不同地形，但能耗大、效率低、速度慢也是目前的主要弊端。为了解决上述问题，提高移动机器人多场景的适应性和通用性，本文设计了一种采用并联机构的多模式轮足混合机器人，并完成了机器人软硬件系统的构建和真机运行测试。该机器人为轮式双足构型，每条腿有三个自由度，分别平行分布在膝关节、髋关节和驱动轮轴处。机器人设计采用轻量化、模块化和质量集中的理念，因此双腿采用五连杆机构，可在膝关节处产生更高功率输出的同时创造更优的整体质量分布结构。机器人软件系统采用基于Linux实时系统的处理器绑定和多线程技术，稳定实现了2 kHz硬件通信频率的并行架构。控制方法上，机器人采用分层控制策略，底层控制器采用简化物理模型和LQR方法，实现了移动、转向和平衡控制，以及对期望状态轨迹的跟踪；上层规划器利用物理约束对机器人状态进行规划，以产生合理可控的运动轨迹。机器人的上身姿态控制则采用添加重力补偿的力位混合控制器，并通过实时的动力学模型更新与平衡控制器耦合。机器人在功能上具有四轮模式和轮式双足模式，并且本文基于该两种模式提出了一种平滑模式切换策略，并在真机上进行了验证。最终，该机器人完成了基础功能的真机运行实验，证明了该轮式双足机器人系统设计的可行性和控制算法的合理性。

With the advancement of technology, mobile robots have become increasingly important in various industries. However, human environments are complex and variable, making it difficult for conventional wheeled robots to navigate rugged terrain. Conversely, although purely legged robots are adaptable to various terrains, they are limited by high energy consumption, low efficiency and slow speed. To address these issues and improve the adaptability and versatility of mobile robots, this paper proposes a multi-mode wheeled-legged robot with a parallel mechanism. The robot has a wheeled-bipedal configuration with three degrees of freedom in each leg, distributed in parallel at the knee joint, hip joint and wheel axis. Design focused on lightweight, modular, and weight concentration concepts, resulting in a five-link mechanism for both legs with a higher power output at the knee joint and better weight distribution. The robot uses a real-time Linux system with processor binding and multi-threading techniques to stabilize the parallel software architecture with 2 kHz hardware communication frequency. The robot uses a hierarchical control strategy, with the lower controllers for motion, steering, balance and following desired state trajectories based on a simplified physical model and the LQR method. The upper planner uses physical constraints to plan the robot state to produce a controllable motion trajectory. In addition, a hybrid force-position controller with additional gravity compensation is used to adjust upper body pose, which couples with the balance controller through updating real-time dynamic model. The robot can be operated in both the four-wheeled mode and the wheeled-bipedal mode, and a smooth mode switching strategy is proposed and validated on a real robot. Finally, the feasibility of design and rationality of the control algorithm was verified through real-world operation and demonstration of all basic functions of the robot.

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