【正文】 因而應(yīng)用這些控制技術(shù)，允許即使是不熟練的司機(jī)也能容易和精確地操控液壓挖掘機(jī)。與不裝補(bǔ)償裝置的情況相比較，圖中的關(guān)表示 不裝時，開的情況具有補(bǔ)償提供穩(wěn)定響應(yīng)。例如，圖 12 表示動臂下降時，采用壓力反饋補(bǔ)償時的測試結(jié)果。5186。對動臂操作桿的手控操作能暫時中斷自動控制，因為手控操作的優(yōu)先級高于自動控制。液壓控制系統(tǒng)控制產(chǎn)生的液壓力與電磁比例閥的電信號成比例，主控閥的滑芯的位置控制流入液壓缸液壓油的流量。（在 SK16 大型液壓挖掘機(jī)進(jìn)行模擬實驗。 實際上，用不同的 △ θ2值可確定 1。 但是，一般很難精確的測出加速度。在半自動控制系統(tǒng)中，為了實現(xiàn)自控與手控的協(xié)調(diào)，必須使用手動的主控閥。Fi是液壓缸的動摩擦力。 。具體闡述如下。在這種情況下，操作手柄的操作表明了執(zhí)行元件的動作方向，但是這種方向與工作方向不同。 關(guān)鍵詞：施工機(jī)械；液壓挖掘機(jī)；前饋；狀態(tài)反饋；操作 1．引言 液壓挖掘機(jī)，被稱為大型鉸接式機(jī)器人，是一種施工機(jī)械。 thus, the effects of the control algorithm described in Chap. 3 were ascertained. . Effect of nonlinear pensation Fig. 11. Effect of nonlinear pensation on boom angle. Because dead zones exist in the electrohydraulic systems, steadystate error remains when simple position feedback without pensation is applied in the figure.. Addition of nonlinear pensation in the figure. can reduce this error. . Effect of state feedback control For the arm and bucket, stable response can be obtained by position feedback only, but adding acceleration or pressure feedback can improve fastresponse capability. As regards the boom, with only the position feedback, the response bees oscillatory. Adding acceleration or pressure feedback made the response stable without impairing fastresponse capability. As an example, Fig. 12 shows the test results when pressure feedback pensation was applied during boom lowering. . Le213。 Ksbulk modulus of oil。 hi scylinder length。Semiautomatic control system for hydraulic shovel Abstract A semiautomatic control system for a hydraulic shovel has been developed. Using this system, unskilled operators can operate a hydraulic shovel easily and accurately. A mathematical control model of a hydraulic shovel with a controller was constructed and a control algorithm was developed by simulation. This algorithm was applied to a hydraulic shovel and its effectiveness was evaluated. High control accuracy and highstability performance were achieved by feedback plusfeedforward control, nonlinear pensation, state feedback and gain scheduling according to the attitude. Keywords: Construction machinery。 Xi sspool displacement。 and csflow coefficient. . Link relations In the model shown in Fig. 1, the relation between the cylinder length change rate and the attachment rotational angular velocity is given as follows: (1)leg (2). arm (3). bucket 當(dāng) 時， Fig. 3. Model of hydraulic cylinder and valve. . Torque relations From the link relations of Section , the supply torque t is given as follows, taking cylinder friction I into consideration: Where, Cci is the viscous friction coefficient and Fi is kiic frictional force of a cylinder. . Response characteristics of the spool Spool action has a great effect on control , we are assuming that the spool has the following firstorder lag against the referenceinput. Where, XX is the reference input of spool displacement and T is a time constant. 3. Angle control system As shown in Fig. 4, the angle u is basically controlled to follow the reference angle u by position feedback. In order to obtain more accurate control, nonlinear pensation and state feedback are added to the position feedback. We will discuss details of these algorithms as follows. Fig. 4. Block diagram of control system . Nonlinear pensation In the ordinary automatic control systems, new control devices such as servo valves are used. In our semiautomatic system, in order to realize the coexistence of manual and automatic operations, we must use the main control valves, which are used in manual operation. In these valves, the relation between spool displacement and open area is nonlinear. Then, in automatic operation, using this relation, the spool displacement is inversely calculated from therequired open area, and the nonlinearity is pensated Fig. 5. Nonlinear pensation. . State feedback Based on the model discussed in Section 2, if the dynamic characteristics for boom angle control are linearized in the vicinity of a certain standard condition?spool displacement X , cylinder differential 10 pressure P , and boom angle u ., the closedloop transfer function can be expressed by where, K is position feedback gain。el crowding control test Control tests were conducted under various controland operating conditions to observe the control Fig. 12. Effect of pressure feedback control on boom angle. Fig. 13. Effect of feedforward control on control error of Z. characteristics, and at the same time to determine the optimal control parameters ?such as the control gains shown in Fig. 6.. .