【正文】 y. The program realizing these functions is primarily written in C language, and has wellstructured module to improve maintainability. 7. Results and analysis of field test We put the field test with the system. We confirmed that the system worked correctly and the effects of the control algorithm described in Chaps. 3 and 4 were ascertained as follows. . Automatic control tests of indi213。 Bi sspool width。 and gsgravitational acceleration. 3 3 g 3 θi is the joint angle, τi is the supply torque, li is the attachment length, lgi is the distance between g ithe fulcrum and the center of gravity, mi is the mass of the attachment, Ii is the moment of inertia around (the center of gravity subscripts is1–3。 Feedforward。 Pi scylinder headside pressure。e gain scheduling according to the attitude In articulated machines like hydraulic shovels,dynamic characteristics are greatly susceptible to the attitude. Therefore, it is difficult to control the machine stably at all attitudes with constant gain. To solve this problem, the adaptive gain scheduling according to the attitude is multiplied in the feedback loop Fig. 6.. As shown in Fig. 7, the adaptive gain (KZ or Ku). is characterized as a function of two variables , and Z. means how the arm is extended, and Z means the height of the bucket. 5. Simulation results The level crowding control was simulated by applying the control algorithm described in Section 4 to the hydraulic shovel model discussed in Section 2. In the simulation, our large SK16 hydraulic shovel was employed.. Fig. 8 shows one of the results. Fiveseconds after the control started, load disturbance Fig. 6. Block diagram of control system (Z). Fig. 7. Gain scheduling according to the attitude. was applied stepwise. Fig. 9 shows the use of feedforward control can reduce control error. 6. Semiautomatic control system Based on the simulation, a semiautomatic control system was manufactured for trial, and applied to the SK16 shovel. Performance was then ascertained by field tests. This section will discuss the configuration and functions of the control system. . Configuration As illustrated in Fig. 10, the control system consistsof a controller, sensors, man–machine interface,and hydraulic control system. The controller is based on a 16bit microputer which receives angle input signals of the boom, arm, and bucket from the sensor。 and 2. when the control interval is less than 50 ms, control performance cannot be improved so much. Consequently, taking calculation accuracy into account, the control interval of 50 ms was selected for this control system. . Effects of load A shovel with this control system carried out actual digging to investigate the effects of loading. No significant difference was found in control accuracy from that at no load. 8. Conclusions This paper has shown that bining state feedback and feedforward controls makes it possible to accurately control the hydraulic shovel, and also showed that nonlinear pensation makes it possible to use ordinary control valves for automatic controls. The use of these control techniques allows even unskilled operators to operate hydraulic shovels easily and accurately. We will apply these control techniques to other construction machinery such as crawler cranes, and improve the conventional construction machinery to the machines which can be operated easily by anyone. References [1] J. Chiba, T. Takeda, Automatic control in construction machines, Journal of SICE 21 8 1982 40–46. [2] H. Nakamura, A. Matsuzaki, Automation in construction machinery, Hitachi Review 57 3 1975 55–62. [3] T. Nakano et al., Development of large hydraulic excavator,. Mitsubishi Heavy Industries Technical Review 22 2 1985 42–51. [4] T. Morita, Y. Sakawa, Modeling and control of power shovel, Transactions of SICE 22 1 1986 69–75. [5] H. Araya et al., Automatic control system for hydraulic excavator, Ramp。開發(fā)出一種讓任何人都能容易操控的液壓挖掘機(jī)就非常必要了 [15]。 開發(fā)這種半自動(dòng)控制系統(tǒng)，必須解決以下兩個(gè)技術(shù)難題。模型的具體描述如下。 在這個(gè)問題上，對(duì)于每一臂桿組件，從液壓缸的壓力流量特性可得出以下方程： 當(dāng) 時(shí)； 其中， Ai是液壓缸的有效橫截面積 。 其中， 是滑芯位移的參考輸入； 是時(shí)間常數(shù)。同時(shí)，非線性是可以補(bǔ)償?shù)模▓D5）。這就是所謂的壓力反饋。 根據(jù)位置自適應(yīng)增益調(diào)度 類似液壓挖掘機(jī)的鉸接式機(jī)器人，其動(dòng)態(tài)特性對(duì)位置非常敏感。圖 9 表示使用前饋控制能減少控制錯(cuò)誤的產(chǎn)生 . 6 半自動(dòng)控制系統(tǒng) 建立在模擬實(shí)驗(yàn)的基礎(chǔ)上，半自動(dòng)控制系統(tǒng)已制造出來，應(yīng)用在 SK16 型挖掘機(jī)上試驗(yàn)。 以上處理后的數(shù)據(jù)都存在存儲(chǔ)器上，可以從通信端口中讀出。 （ 3）手控操作模式：當(dāng) 既沒有選擇反鏟水平動(dòng)作模式，也沒有選擇鏟斗水平舉升模式時(shí)，動(dòng)臂，斗柄，鏟斗都只能通過手動(dòng)操作。因?yàn)殡娨合到y(tǒng)存在不靈敏區(qū)，當(dāng)只有簡(jiǎn)單的位置反饋而無補(bǔ)償時(shí)（圖11 中的關(guān)）穩(wěn)態(tài)錯(cuò)誤仍然存在。采用第 節(jié)所描述的斗柄臂桿前饋控制能減少錯(cuò)誤而不致于增大 Kp。 因此，考慮到計(jì)算精度，控制系統(tǒng)選定控制間隔為 50ms。D Kobe Steel Engineering Reports 37 2 1987 74–78. [6] . Vaha, . Skibniewski, D