多关节机器人仿生液压驱动技术及效率研究

发布时间：2018-06-29 20:06

本文选题：仿生机器人 + 多执行器液压系统　；参考：《国防科学技术大学》2016年博士论文

【摘要】：随着仿生机器人性能的不断提升,其运用范围不断扩大,而传统采用电机驱动的仿生机器人由于负载能力有限,难以执行较大负载的任务,譬如特殊地形战场携带武器装备的作战任务、地震灾区携带救灾设备的搜救任务等,因此具备大负载和高机动性能的液压驱动的仿生机器人越来越受到人们的重视。然而,由于体积和重量的限制,仿生机器人液压驱动系统大多都采用单泵源多执行器的结构,但在机器人的运动过程中,不同的执行器在同一时刻的负载差异显著,同一执行器在不同时刻的负载变化也非常剧烈,使得系统供油压力与执行器负载所需压力的匹配状态较差,从而导致液压系统的能量利用效率较低,严重制约了该类机器人的实用化进程。针对仿生机器人液压系统效率低下这一问题,本文分别从液压系统能量供给与能量输出两个方面研究提高系统供给压力与负载所需压力的匹配度,从模仿人体多级能量供给方式和肌肉结构及其不同输出力的调节方式的角度出发,提出了仿生多级供能的液压系统以及仿生液压执行器,并展开了深入研究。本文主要研究思路和内容包括以下几点:(1)分析了导致典型的单泵多执行器仿生机器人液压系统效率低下的原因。本文以具有16个执行器的仿生四足机器人为例进行分析,分析了该机器人在原地蹲起、转弯和对角小跑三种典型步态下的液压系统效率,并指出导致效率低下的原因。针对这一原因,通过分析人体的多级能量供给方式和肌肉结构及其输出力的调节方式,提出了仿生液压驱动的基本思想。(2)深入开展了仿生多级供能液压系统的设计与分析。模仿人体的多级能量供给方式提出了仿生多级供能的液压系统设计机理。在该机理的指导下,提出一种可行的基于分布式微小型瞬时高压蓄能器的两级供能液压系统,该系统利用微小型高压蓄能器构建瞬时高强度运动的能量供给系统,利用低压大流量泵源作为长时低强度运动的能量供给系统。然后,通过建立能量损耗模型,分析指出了该两级供能系统比典型的单级供能系统节能的主要原因。(3)提出了一种基于PWM(Pulse Width Modulation)控制的压力调节方法。为了进一步改善两级供能液压系统的长时间低强度供能时的压力匹配状态,提出一种新型的压力调节器FPC(Fluid Power Converter)。FPC是利用机械能与液压能之间的转化来实现对输出压力和流量的调节,该压力调节方式与常规使用的节流(阻尼)调压方式不同,具有较高的能量利用效率的特点。本文详细阐述了FPC的原理,对关键的惯性元件的结构进行了详细设计。通过建立FPC的数学模型,对其性能进行了详细分析。分析结果表明FPC在进行压力和流量条调节过程仍能保持较高的能量利用效率。(4)深入开展了仿生液压执行器的设计与分析。模仿人体肌肉的多纤维和多运动单元的结构特征以及肌肉与负载进行匹配时的运动单元募集方式,提出了仿生液压执行器的设计机理以及负载匹配控制策略。在该机理的指导下,对一类仿生液压执行器结构进行了详细设计、分析和优化,并给出了多种结构拓展方案。通过建立仿生液压执行器与传统液压执行器的能量损耗模型,对比指出了仿生液压执行器比传统液压执行器节能高效的原因。最后,根据本文提出的负载匹配控制策略,利用仿真方法对仿生执行器的负载匹配控制进行了研究。(5)对本文提出的仿生两级供能液压系统和仿生液压执行器进行了仿真验证。以本文设计的四足机器人为对象,分别建立了加入FPC前后的两级供能系统和基于仿生高效执行器的液压系统的仿真模型并进行仿真分析,结果表明本文所提出的方法均能够提高能量利用效率。(6)为了进一步验证仿生执行器的负载匹配和节能特性,本文研制了三种结构的仿生液压执行器原理样机和单臂试验平台。通过测试不对称结构和对称结构的两种仿生执行器的液压缸的摩擦力,表明优化后的仿生执行器具有较好的结构稳定性。最后,进行了仿生执行器驱动机械臂提起不同负载的试验,试验结果表明仿生执行器能够通过负载匹配调节达到节能高效的目的。本文提出的仿生多级供能液压系统和仿生执行器的设计机理对仿生机器人液压系统设计提供了理论指导,同时提出的两级供能系统和仿生液压执行器对促进液压驱动的仿生机器人的实用化进程具有积极的意义。另外,本文提出的方法具有一定的通用性,同样可用于提高具有多执行器的工程机械的液压系统效率,因此具有一定的经济价值。
[Abstract]:With the continuous improvement of the performance of the bionic robot, the application scope of the robot is expanding, and the traditional bionic robot driven by the motor is difficult to carry out the task of large load because of the limited load capacity. For example, the special terrain battlefield carries the operational task of the weapon and equipment, the earthquake stricken area carries the search and rescue task of the disaster relief equipment and so on. The bionic robot driven by load and high maneuverability has been paid more and more attention. However, because of the limitation of volume and weight, most of the hydraulic driving systems of bionic robot adopt the structure of single pump source multi actuator, but in the process of robot movement, the difference of the load of different actuators at the same time is remarkable. The load change of an actuator at different times is also very intense, which makes the matching state of the pressure of the system oil supply and the load required for the actuator is poor, which leads to the low efficiency of the energy utilization of the hydraulic system, which seriously restricts the practical process of this kind of robot. This paper is aimed at the problem of the low efficiency of the hydraulic system of the bionic robot. From the two aspects of the energy supply and energy output of the hydraulic system, the matching degree of the pressure of the system supply pressure and the load required is studied. The bionic multistage energy supply hydraulic system and the bionic hydraulic actuator are proposed from the angle of imitation of the human multistage energy supply mode and the adjustment mode of the muscle structure and the different output forces. The main research ideas and contents of this paper include the following points: (1) the reasons for the low efficiency of the typical single pump multi actuator bionic robot hydraulic system are analyzed. In this paper, a bionic quadruped robot with 16 actuators is analyzed, and the robot is squatted, turned and diagonally small. The hydraulic system efficiency under three typical gait is run and the cause of low efficiency is pointed out. According to this reason, the basic idea of bionic hydraulic drive is put forward by analyzing the multistage energy supply mode of human body and the adjusting mode of muscle structure and its output force. (2) the design and division of the bionic multistage energy supply hydraulic system are carried out in depth. The design mechanism of the bionic multistage energy supply system is proposed by imitating the multistage energy supply mode of the human body. Under the guidance of this mechanism, a feasible two stage energy supply hydraulic system based on the distributed micro instantaneous high pressure accumulator is proposed. The system uses a micro high voltage accumulator to build the energy supply of the instantaneous high intensity motion. The system uses the source of the low pressure and large flow pump as the energy supply system for long and low intensity movement. Then, through the establishment of the energy loss model, the main reasons for the energy saving of the two stage energy supply system are pointed out. (3) a pressure regulation method based on PWM (Pulse Width Modulation) control is proposed. A new type of pressure regulator FPC (Fluid Power Converter).FPC is proposed to adjust the pressure and flow rate between the mechanical energy and the hydraulic energy, and the pressure regulating mode and the conventional throttle (damping) adjustment are used to improve the pressure matching state of the two stage energy supply hydraulic system with long time and low strength. The principle of FPC is described in detail and the structure of the key inertial components is detailed. The performance is analyzed in detail by establishing a mathematical model of FPC. The results show that the FPC can still maintain high energy in the process of regulating pressure and flow strip. (4) the design and analysis of the bionic hydraulic actuator are carried out in depth. The structure characteristics of the multi fiber and multi motion unit of the human muscle and the way of raising the motion unit when the muscles and the load are matched are proposed. The design mechanism of the bionic hydraulic actuator and the control strategy of the load matching are put forward. The guidance of the mechanism is guided. Then, the structure of a kind of bionic hydraulic actuator is designed, analyzed and optimized, and a variety of structure expansion schemes are given. By establishing the energy loss model of the bionic hydraulic actuator and the traditional hydraulic actuator, the reasons of energy saving and efficiency of the bionic hydraulic actuator than the traditional hydraulic actuator are compared. Finally, the paper proposes the paper. The load matching control strategy is developed, and the simulation method is used to study the load matching control of the bionic actuator. (5) the simulation verification of the bionic two level power supply hydraulic system and the bionic hydraulic actuator proposed in this paper is carried out. The four legged robot, which is designed in this paper, is used to establish the two level energy supply system before and after the FPC. Simulation model of hydraulic system based on bionic high efficiency actuator and simulation analysis show that the proposed method can improve the efficiency of energy utilization. (6) in order to further verify the load matching and energy saving characteristics of the bionic actuator, three kinds of bionic hydraulic actuator prototype and single arm test are developed in this paper. By testing the friction force of the hydraulic cylinders of two kinds of bionic actuators with asymmetric and symmetrical structures, it is shown that the optimized bionic actuator has better structural stability. Finally, the bionic actuator drives the mechanical arm to lift the different loads. The experimental results show that the bionic actuator can be adjusted by the load matching. The design mechanism of bionic multistage energy supply hydraulic system and bionic actuator proposed in this paper provides theoretical guidance for the hydraulic system design of bionic robot. At the same time, the two stage energy supply system and the bionic hydraulic actuator have positive significance to the practical process of promoting the hydraulic driven bionic robot. In addition, the method proposed in this paper has a certain generality and can also be used to improve the efficiency of the hydraulic system of engineering machinery with multiple executor. Therefore, it has certain economic value.
【学位授予单位】：国防科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP242

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