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1、Hydraulic excavatorssemi-automatic controlled system AbstractA hydraulic excavators used in the semi-automatic controlled system is developed. Because of this system, even unskilled operators can easily and accurately controlled hydraulic excavators. Constructed with the hydraulic excavator controll
2、er of mathematical precision control model through simulation to develop a control algorithm, which is used in hydraulic excavators, We can estimate its efficiency. In accordance with the law, through positive feedback and feed forward control, nonlinear compensation. state feedback and gain schedul
3、ing, and other means to obtain higher accuracy and stability properties. Keywords : construction machinery; Hydraulic excavators; feed forward; State feedback; Operation 1 Introduction hydraulic excavators, known as the large articulated robot, a construction machinery. Using this machine excavation
4、 and loading operations, require drivers to have high operational skills, Even skilled driver would have considerable fatigue. The other hand, with the operators age increased, the number of skilled drivers thus will be reduced. Developed a way to let anyone will be able to easily manipulate the hyd
5、raulic excavator is very necessary. Hydraulic excavators asked for a higher operational skills, for the following reasons. 1. Hydraulic excavator operation, at least two joystick operation and must be coordinated.2. Joystick moves charged with the direction of the Jib components of the campaign in d
6、ifferent directions. For example, the hydraulic excavator backhoe level action, we must also play three joystick (boom, the bucket handles, Bucket) to enable the bucket along the top of the horizontal movement. In this case, joystick operation shows the components of the implementation of the direct
7、ion of movement, but this direction and work in different directions. If a driver to operate as long as the control rod, bar and other free arm automatic servo action, operation becomes very simple. This is the so-called semi-automatic control system. Development of a semi-automatic control system,
8、we must address the following two technical problems. 1. Automatic control systems must use common control valve. 2. Hydraulic excavators must compensate its dynamic characteristics to improve its accuracy.2 Hydraulic excavator model To study the hydraulic excavator control algorithm, hydraulic exca
9、vators must analyze the mathematical model. The hydraulic excavator boom, the bucket handles, and the bucket is driven by fluid pressure. 2.1 Dynamic model Assumes that each of the Jib components are rigid, the Lagrange equations of motion can be in the following expression : where g is the accelera
10、tion due to gravity; i hinged angle; i is the component of torque ; li length; lgi shaft to the centers focus away from the quality ;mi components; Ii is the focus of the moment of inertia (subscript i=1-3; were expressed boom, the bucket handles, and the bucket). 2.2 Excavator model Components of e
11、ach arm are driven by hydraulic cylinder, hydraulic cylinder and flow control of the slide valve. Can make the following assumptions : 1. Hydraulic valve opening and valve core proportional to the displacement. 2. System hydraulic oil leak. 3. Hydraulic oil flows through the pipeline when no hydraul
12、ic pressure loss. 4. Cylinder rod and the top of both sides are equally effective regional. On this issue, each arm components from the hydraulic cylinder pressure and flow characteristics may come to the following equation : When; Among them, Ai hydraulic cylinder is an effective cross-sectional ar
13、ea ;hi hydraulic cylinder is the length ;Xi sliding core is the location; Psi ;P1i of supply pressure is the maximum cylinder pressure ;P2i side of the cylinder rod edge pressure; Vi is the hydraulic cylinder and the oil pipeline is ;Bi slide valve width; is the density of oil molecules, K oil visco
14、sity; c is the flow coefficient. 2.5 Slide valve characteristic Slide valve movement of the hydraulic excavator control characteristics have considerable influence. Thus, the assumption that Valve relative reference input following an order delay. Which is sliding core displacement reference input;
15、Is time constant. 3 angle Angle control system is basically a servo reference input through the angle position feedback control. To obtain more accurate control, nonlinear feedback and compensation by adding location feedback. 3.1 nonlinear compensation In ordinary automatic control systems, often u
16、sed as servo valve of this new type of control device. In semi-automatic control system, in order to achieve automatic control and manual coordination, the use of manually controlling the valve. This type valve, the displacement of the spool valve with the opening of the relationship is nonlinear. Therefore, the control operation, the use of such a relationship, spool displacement may be required by the
