With the rapid development of market economy, aerial work equipment has been widely used in fire control, municipal street lamp, environmental sanitation, electric power, airport, ship repairing and building, port machinery manufacturing and other industries. The existing aerial work equipment is to transport the people or objects in the working groove to the working area by lifting, stretching and rotating of the working arm. In order to prevent the high-altitude operation equipment from tipping over and causing casualties, the working arm sets different working radius at various angles. The continuous curve made of the working radius is called In order to make the working arm work in the safe working range all the time, the controller must collect the signal value of the telescopic length of the working arm Displacement sensor Is used to provide this signal value.
The most commonly used length sensor is the pull wire length sensor. It includes a shell, a spindle, a return spring, a pulling wheel and a length data processor. The fixed end of the return spring is connected with the shell, and the free end is connected with the main shaft. The cable wheel is installed on the main shaft and can rotate synchronously with the main shaft. The cable can be wound on the cable wheel, and the outer end of the cable extends outward and is connected with the end of the arm body. The end of the arm body corresponds to the root of the arm, and the two can produce relative motion. The return spring can produce a reset force to keep the part outside the shell in a straight line. When the force on the outer end of the cable is reduced, it can drive the main shaft and cable wheel to rotate, and then the cable is wound on the cable wheel. The working principle of the length sensor is as follows: when the end of the arm body is far away from the root of the arm body, the outer end of the cable is pulled to move together; the cable wheel drives the cable wheel, and the cable wheel drives the main shaft to overcome the rotation of the return spring; at the same time, the reset spring is tightened to produce a reset force; Because the moving distance of the outer end of the stay wire is proportional to the number of turns of the main shaft, the length data processor can measure the number of turns of the main shaft, and then according to the predetermined proportion relationship, the distance of the outer end of the cable can be obtained; and then the moving distance of the end of the arm body relative to the root of the arm body can be obtained to realize the measurement of the length data. When the end of the arm body is close to the root of the arm body, the return spring drives the main shaft to reverse, and the main shaft drives the cable wheel to reverse, so that the cable is wound on the cable wheel again.
However, if the length of the boom is not fixed within the working range of the boom, it will cause the boom to fall off at a certain value.
summary of the invention
Object of the invention: the invention aims to provide a pulling rope according to the deficiency of the prior art Displacement sensor The detection method of stay wire state can detect the working state of stay wire in real time, and then limit the working arm to the safe operation range.
(1) The controller can automatically sample and compare the length value of the rope displacement sensor, judge the working state of the stay wire, and make the aerial work equipment always in the safe working area;
(2) The invention can send out an alarm when detecting the abnormal state of the stay wire, and at the same time limit all actions of the aerial work equipment, greatly improve the safety of the aerial work equipment and reduce the occurrence of accidents.
Description of drawings
Fig. 1 is the flow chart of the detection method for the pull wire state of the pull rope displacement sensor of the invention;
Fig. 2 is the hardware connection diagram of the detection method for the pull wire state of the pull rope displacement sensor of the invention.
Specific implementation mode
However, the scope of the present invention is not limited by the following technical examples.
Implementation example: a method for detecting the pulling state of a rope displacement sensor, which is used to detect the length of the working arm of the aerial work equipment, comprises the following steps:
(1) The current signal of the telescopic solenoid valve of the working arm is detected;
(2) When the current signal I of the telescopic solenoid valve of the working arm is 0, the counter samples the length value signal of the rope displacement sensor every 5 seconds or 20 seconds;
(3) Compare the sampling values of two sampling points with an interval of 5 seconds or 20 seconds: if the two sampling values are not the same, it is judged that the pull wire state is normal; repeat steps (2) - (3) to enter the next detection cycle;
(4) If the two sampling values are the same, it is judged that the pull wire state is abnormal, and alarm is given by the controller and all actions of the aerial work equipment are limited.
As mentioned above, although the invention has been expressed and described with reference to specific preferred embodiments, it shall not be interpreted as a limitation of the invention itself. Without departing from the spirit and scope of the invention as defined in the attached claims, various changes in form and details may be made.