基于流量规划的液压悬架负负载调速控制

Negative-load Velocity Control of Hydraulic Suspension Based on Flow Mapping

针对重型运输车液压悬架负负载下降速度不均匀、不稳定问题,提出一种基于流量规划的液压悬架负负载调速方案。首先根据悬架倾角传感器和手柄指令速度信号计算平衡阀理论输出流量,而后依据预先建立的平衡阀流量映射关系,采用线上查表和插值方法求值并通过比例溢流阀输出平衡阀所需控制压力,使其输出流量实时跟随理论流量,从而控制悬架下降速度实时跟随手柄指令信号。建立了控制方案的稳态数学控制模型,并在某型号运梁车上进行试验研究,研究结果表明,该方案能够将悬架空载下降速度变化率从33%降至17%、悬架重载下降速度变化率从40%降至15%;且在平衡阀流量不饱和情况下,悬架空载/重载悬架最大下降速度之差从200 mm/min降至10 mm/min,悬架下降速度的均匀性和稳定性显著提高。该方案较易在工程中实现,且具有较大的工程应用价值,为基于平衡阀的液压系统负负载调速控制提供一个新的思路。

Aiming at the problem of non-uniformity and instability of the negative-load falling speed of the hydraulic suspension in heavy transport vehicle,a negative-load speed regulation strategy scheme based on flow mapping was proposed.Based on the pre-established flow mapping of the counterbalance valve,the control strategy calculates the theory output flow of the counterbalance through inclination sensors and the speed order of the handle.Then the control system adjusts the flow of the counterbalance valve to follow theory flow by adjusting the control pressure of the counterbalance valve through proportional relief valve,which is calculated by online look-up table and interpolation method,so as to control the suspension descending speed to follow the command speed signal in real time.The steady-state mathematical model of the control scheme was established,and the experimental investigations were carried out on a beam carrier.Experimental results show that the proposed scheme can reduce the speed variation rate under no-load condition from 33%to 17%and reduce the speed variation rate under heavy-load condition from 40%to 15%,and that under the conditions where the counterbalance valve is not saturated,the difference between the maximum falling speeds of the suspension under no-load/heavy-load conditions is reduced from 200 mm/min to 10 mm/min,which significantly improved the uniformity and stability of the falling speeds of the suspension under different loads.The proposed scheme is easy to implement in engineering and has great practical application value,providing a new control idea for the negative-load speed regulation control of the hydraulic system based on counterbalance valves.