摘 要

随着科技发展，人们对于自然的探索日渐频繁，作为替代人类执行野外科考、太空探索、深海勘测等任务的移动式机器人也逐渐成为了人们研究的热点。目前的主流移动式机器人可按照移动机构的不同分为轮式机器人、履带式机器人和足式机器人三类。受限于移动机构的能力，这三种移动机器人均有其特定的使用场所，在其他环境中则运动性能大幅降低，不能很好的适应探索中遇到的复杂且多变的地形。为了解决这一难题，人们开始结合不同移动机构的优势，开发复合移动机构机器人。复合移动机构机器人具有多种移动机构，因而可以根据所处环境自由地调整运动方式，能够很好地适应复杂地形。轮足式机器人就是其中一种，其具备轮、足两种移动机构，且能在运动过程中自由切换，是当下移动机器人的研究趋势之一。

本文结合近年来轮足式移动机器人的发展现状，设计了一种基于臂式主动悬架的轮足分离式轮足机器人。臂式主动悬架的优点在于可以通过调节纵臂的角度，实现车身高度可调，同时具有较好的缓冲减振能力。为完成轮足机器人的整体设计工作，本文依次进行了机器人总体设计、轮足总成的设计、转向系统的设计、车身结构设计和整体装配四个部分的设计工作，并利用Solidworks软件完成了机器人整体的建模与装配。此外，在设计过程中通过有限元仿真分析，运动姿态规划和仿真对机器人的结构进行了分析与验证，证明了设计的合理性和可靠性。本文设计的轮足式机器人结构简单，兼具轮式、足式两种运动方式的优点，具有较好的运动和缓冲减振性能，为后续的结构优化设计和步态规划提供了思路与理论依据。具体研究内容包括以下几个方面：

1）机器人总体设计。对拟设计的轮足机器人进行了定义，确定了其尺寸及性能指标，得到设计参数表。对轮足机器人进行了动力系统的设计计算，根据机器人的性能指标计算了轮毂电机和电池的参数，对附着条件进行了校核，并完成了轮毂电机和电池的选型。分析了轮足机器人控制系统的功能需求，并对电机控制器进行了选型。

2）轮足总成的设计。通过对四足生物腿部结构的研究确定了机器人轮足结构的形式，通过设计计算完成了机器人腿部结构的设计，在髋关节处引入了臂式主动悬架系统。对机器人轮、足两种运动姿态进行了规划，分析了轮足机器人的运动能力。计算了机器人腿部关节的输出扭矩，完成关节电机的选型。对大小腿进行了有限元强度验证，证明了轮足结构设计的可靠性与合理性。

3）转向系统的设计。根据轮足结构提出了基于整桥的转向方案。根据机器人最大转向力矩确定了转向驱动方案。设计了转向机构，并选型电机。对机器人行驶转向和特殊转向机动动作进行了规划与分析，验证了机器人的转向能力。对转向系统的主体进行了有限元分析，验证了其在各工况下的结构强度，证明了设计的合理性和可靠性。

4）车身设计与总体装配。根据机器人的外廓尺寸和转向系统的结构设计车身框架，根据控制及动力系统元件类型及尺寸确定其安装方式，完成了车身结构的设计。对车身进行有限元分析，验证了其结构强度。对机器人进行整体装配，得到装配体模型，计算了机器人整体质量，验证了其质量满足设计要求。

5）运动学仿真分析。对机器人轮足切换、转向、越障三个工况进行仿真，验证了机器人离地间隙、转向半径、越障高度等指标，证明了机器人结构设计的合理性和轮足两种运动姿态的运动能力。

关键词：轮足式机器人；臂式悬架；结构设计；有限元；运动仿真

Abstract

With the development of science and technology, people are exploring the nature more and more frequently. As a substitute for human to carry out field research, space exploration, deep-sea exploration and other tasks, mobile robots have gradually become a research hotspot. At present, the mainstream mobile robots can be divided into three categories: wheeled robot, crawler robot and foot robot. Limited by the ability of mobile mechanism, these three kinds of mobile robots have their own specific places of use. In other environments, the motion performance is greatly reduced, which can not adapt to the complex and changeable terrain encountered in exploration. In order to solve this problem, people began to combine the advantages of different mobile mechanisms to develop composite mobile robot. The robot with compound mobile mechanism has many kinds of mobile mechanisms, so it can adjust its motion freely according to its environment, and can adapt to the complex terrain well. Wheel foot robot is one of them. It has two kinds of mobile mechanisms: wheel and foot, and can switch freely in the process of motion. It is one of the research trends of mobile robot.

Based on the development of wheel foot mobile robot in recent years, this paper designs a wheel foot separated robot based on in-arm active suspension. The advantage of the in-arm active suspension is that the height of the body can be adjusted by adjusting the angle of the longitudinal arm, and it has a better damping capacity. In order to complete the whole design of the wheel foot robot, this paper successively carries out four parts of the design work: the overall design of the robot, the design of the wheel foot assembly, the design of the steering system, the design of the body structure and the overall assembly, and uses SolidWorks software to complete the whole modeling and assembly of the robot. In addition, in the design process, the structure of the robot is analyzed and verified through the finite element simulation analysis, motion attitude planning and simulation, which proves the rationality and reliability of the design. The wheel foot robot designed in this paper has the advantages of simple structure, both wheel and foot motion modes, and has better motion and shock absorption performance, which provides ideas and theoretical basis for the following structural optimization design and gait planning. The specific research content includes the following aspects:

1) Overall design of robot. This paper defines the wheel foot robot to be designed, determines its size and performance index, and obtains the design parameter table. The power system of the wheel foot robot is designed and calculated. The parameters of the wheel motor and the battery are calculated according to the performance index of the robot. The adhesion condition is checked and the selection of the wheel motor and the battery is completed. The functional requirements of the control system of the wheel foot robot are analyzed, and the motor controller is selected.

2) The design of the wheel-foot system. Based on the research of quadruped biological leg structure, the form of the robot's wheel-foot structure is determined. Through the design and calculation, the leg structure of the robot is designed, and the in-arm active suspension system is introduced at the hip joint. In this paper, two kinds of motion postures of the robot wheel and foot are planned, and the motion ability of the robot wheel and foot is analyzed. The output torque of the robot leg joint is calculated and the joint motor is selected. The strength of large and small legs is verified by finite element method, which proves the reliability and rationality of the design of wheel foot structure.

3) Design of steering system. According to the wheel foot structure, a steering scheme based on the whole bridge is proposed. According to the maximum steering torque of the robot, the steering driving scheme is determined. The steering mechanism is designed and the motor is selected. The turning ability of the robot is verified by the planning and analysis of the turning and special turning maneuvers of the robot. The main body of the steering system is analyzed by the finite element method. The structural strength of the steering system under various working conditions is verified, and the rationality and reliability of the design are proved.

4) Body design and general assembly. According to the outline dimension of the robot and the structure of the steering system, the body frame is designed. According to the type and size of the control and power system components, the installation mode is determined, and the body structure is designed. The structural strength of the car body is verified by the finite element analysis. The robot is assembled as a whole, the assembly model is obtained, and the whole mass of the robot is calculated, which proves that the mass meets the design requirements.

5) Kinematic simulation analysis. The three working conditions of wheel foot switch, turning and obstacle crossing of the robot are simulated to verify the ground clearance, turning radius, obstacle crossing height and other indicators of the robot, and to prove the rationality of the robot structure design and the movement ability of the two motion postures of wheel foot.

Keywords: Wheel-foot robot; In-arm suspension; Structure design; Finite element analysis; Motion simulation