On Positioning And CAN-based Distributed Control Of Double Triangle Boom Of Rock-drilling Robot

Reliability and positioning precision of rock-drilling robots, especially of theircontrol system, are important factors for tunnel construction quality and economiccost. The studies on these aspects have been done as following:1. Summarizes the development progress of automatic control system ofrock-drilling robot, and introduces its current situation with Atlas'slatest fully-computerized drill rig-Rocket Boomer L1C/L2C/L3C-asan example. Then proposes that modularized software and hardwaredesign, distributed control, network service and 3D graphic display arethe main trend in the future development. Analyses the control systemof the first rock-drilling robot in China, and points out key problems forfurther research.2. Establishes link coordinates of triangular arrangement of boomincluding two lift cylinders, and then the kinematics equations based onrestrictions of multi-closed-chain. Solving process of the equationsgives an important result, which is that with extra measurement pointsof pitch angle of supporting cylinders, the formula of cauculating thelength of supporting cylinder from the given position of the boom canbe greatly simplified, which will reduce the amount of mathematicaloperations in real-time control, and improve the precision for trajectorycontrol of triangle boom. Incremental equations are derived to calculatethe length of hydraulic cylinder actuators from joint variables ofdouble-triangle-boom online. A new boom positioning control systemstructure is proposed based on the incremental equations, which usesjoint variables, other than the length of actuator cylinders to close theloop.3. Simulation under MATLAB is used to verify the correctness of theequations and control system structure proposed above. Because thedouble-triangle-boom is a MIMO cross coupling and nonlinear systemin nature, it is hard to obtain its dynamic model in algebraically closedform, and ADAMS model is built and exported into MATLAB tocontinue the simulation. The simulation result for an actual boomshows that the incremental equations, derived from infinitesimalincrement, can be used in large variable range, and the computational error makes a slight trajectory deviation from reference straight linewhile makes no final positioning error, which is important in actualsituation. Dynamical de-coupling has been achieved for motionactuating of double-triangle-boom.4. Experimental master-slave control system has been developed withmaster PC as monitoring unit and slave Siemens PLC as measurementand control unit in laboratorial dill rig. A lot of experiments show thatthe above algorithm is correct and control system structre based onjoint variables is feasible, offering a foundation for more accuratepositioning of double-triangle-boom.5. Analyses the control system components of rock-drilling robot.Designs an independent CAN-bus distributed control system for eachboom to avoid disadvantages of centralized control. Assigns four kindsof intelligent nodes on CAN-bus, which correspond to operator panel,sensors, actuators, and micro-controller. Defines CAN2.0A 11-bitidentifier according to node type and signal type for real time demand.Proposes requirements of communication design of intelligent nodesfor coordinating signal flow and reducing time consumption of busconflict and arbitration on CAN-bus.6. In allusion to above distributed control system, constructs theintelligent operator panel node on CAN-bus after analyzing its signaltypes. Gives three types of definition of state parameters of joystick,and the conversion formula of them. Devises a new digital joystickbased on MEMS Dual Axis Accelerometer ADXL202 using gravity asa positional reference, and designs its hardware and software. Anintegral coefficient LP filter algorithm is designed, based onmicro-controller which has a limited floating-point ability, suitable forworking environment of drilling rig. Because of the nonlinearrelationship between output acceleration and input angle, thestraight-line segments of equal-error method is used here to approachthis nonlinear curve to enlarge the linear range of output control valuewith less nodes of interpose and less calculation in micro-controller. Aniteration approximation algorithm is proposed to calculate the nodes,which is more complicated with direct solving.7. To debug the joystick and inspect its function, a debug environment is designed based on VC++6.0, which can be used to download programto MCU, calibrate sensors, read data from joysick, and test its functionthrough RS232. This environment can also be used to study thefrequency spectrum of vibration and shock of drill rig workingcondition, which, because ADXL202 is an accelerometer sensor, offerreliable cutting frequency for digital filter.3D visualized technique can be used to build visual rig system for operatingtraining, to display real scene and boom for improving operate-environment,releasing operator's stress and tiredness, to visualize the tunneling data to understandthe rock condition for improving the design of blast hole. 3D model display andcontrol based on LabView is proposed to visualize the double triangle boom. AnActiveX control of joystick is created in VC++6.0 and is used to operate doubletriangle boom in LabView.