The starting point of the driver's judgment The starting process can be divided into a variety of operating conditions depending on the driver's intention to control. The driver can control the speed required to be divided into a slow start, a normal start, and an emergency start. The starting point of the driver must be based on environmental information to determine the speed of start, and reflected to the accelerator pedal and engine speed, and the driver's starting intention is usually judged by 3 messages: a. throttle opening. The large throttle opening indicates that the driver is eager to get off the ground. Although it will cause a greater degree of impact, it should complete the starting process relatively quickly. Conversely, the throttle opening is small, the driver is not in a hurry to start and should be slowly joined to ensure better The comfort. b. The rate of change of throttle opening. The rate of change of the accelerator opening is also an important parameter that reflects the driver's intention to start. The faster the change, the brighter he wants to start faster. On the contrary, if the change is slower, the start requirement is also slower. c. Engine speed. When the accelerator opening is equal to zero, if the engine speed is greater than the idling value, the start-start process is in progress; if it is less than or equal to the idling value, the start-up process is cancelled. Start-up control strategy At present, in the clutch start-up control strategy adopted in the country, the control of the clutch engagement speed adopts engine-set speed control and constant-speed control. Active Throttle Control Start-up Strategy The automatic clutch used in the automatic transmission system is pneumatically actuated, the throttle is controlled actively (internal throttle control engine speed), the engine is a diesel engine, and large vehicles are the subject of research. The starting control strategy of clutch pneumatic drive was studied and a joint method was used as a control method. Only the time is detected, and during the corresponding time period, "speed" control is achieved by controlling the opening and closing of the corresponding solenoid valve. The engagement speed during clutch engagement is not constant, but changes with the spring rate of the butterfly spring and the cylinder air pressure. The main indicator of control is the degree of impact, that is, the degree of impact is not greater than the maximum allowed J ≤ Jmax = 17m/s3. Clutch engagement speed Clutch engagement speed is achieved using a split-speed approach. The principle is: During the joining process, it should be ensured that the impact degree does not exceed the allowable range Jmax ≤. The slow start four process engagement speeds are (vc, 0. 5vc, 0. 25vc, 0. 75vc); normal start 4 Process (vc, 0175vc, 0. 5vc, vc); 4 steps to start (vc, 0. 75vc, 0. 75vc, vc). The throttle control of the engagement process adopts active throttle control. The control system can adjust the accelerator opening to solve the above problem. For this purpose, the magnitude of the starting resistance torque needs to be known. To solve the drag torque based on the driving equation of the car, a series of values ​​such as vehicle weight, slope, and road coefficient must be obtained. These values ​​are not fixed and must be detected by sensors. Installing too many sensors will make the control system too complicated. The upper and lower engine speed limits are set for slow start, normal start and emergency start respectively, and the increase or decrease of the accelerator opening degree is determined according to the comparison between the engine speed and the upper and lower limits of the set speed in the starting process. Experiments To analyze the starting strategy, the engine speed (ne) and the speed of the transmission input shaft (nc) were monitored during the experiment. Taking into account the real-time nature of the rotational speed test, 180 and 90 pulsed photosensors per revolution were installed on the input shaft of the engine and the transmission respectively. One set of data is detected every 200ms, and the relationship between the speed and impact of the clutch master and slave disks and the time is plotted according to the data. The impact of the analysis can be seen, the impact of slow start and normal start does not exceed the set maximum; fast start mainly reflects the driver's intention, the impact of the degree greater than the maximum set. The actual vehicle experiments show that the starting strategy using active throttle control has the following features: a. It can reduce the sliding work and improve the service life of the clutch. Practice shows that the lower the rotational speed is, the smaller the sliding friction work is. Controlling the maximum speed of the engine can reduce the sliding work. b. It can reduce emissions and reduce fuel consumption. Active throttle control starting strategy, the accelerator pedal accelerator opening value does not participate in the engine speed control, only as a starting point and the engine throttle maximum throttle output speed corresponding to the determination of the corresponding speed value, the engine throttle value through the ECU After processing, it is given by DAC0. Under normal circumstances, the engine gets a throttle opening value less than accelerator pedal opening value. c. Can adapt to the start-up environment mutation status. When the starting environment changes, the active throttle control starting strategy can adjust the throttle opening size, so that the engine speed and output torque changes, to ensure the completion of the starting process. In the conclusion, the requirements of the clutch control and the control objectives during the start of the vehicle are analyzed. Through the analysis of the clutch engagement process, the factors affecting the vehicle impact and the clutch slip work are clarified. In order to obtain a good start quality, the clutch engagement speed and the engine must be determined. The speed is coordinated and controlled. The common modes and characteristics of the clutch engagement control are studied. According to the particularity of the clutch's pneumatic drive, the active control strategy for starting the throttle is proposed. According to the requirements of the maximum impact degree, the determination methods of the engagement speed and the starting point of each stage in the starting stage are formulated, and the joint speed is comprehensively determined in combination with the structural features of the cylinder and the gas valve.
A Tower Crane is an inverted L-shaped structure that is capable of lifting several tons of weight to precarious heights.
The most striking feature of this crane is that it is self-building and can allow a building to be constructed adjacent to or even around it.
Tower crane mast section ( tower crane mast and tower crane basic mast ) is a steel structure with a normally square section, whose main mission is to provide the tower crane with sufficient height.
Normally it is formed by lattice modules that facilitate the transport of the crane. For assembly, these modules will be joined by screws, all of which will be connected to the projected height. Its shape and dimension vary according to the necessary characteristics of weight and height.
BQ also supplying other Steel Structure spare parts of tower crane like Basic Mast Section, Fixing Angle (or Reusable Fixing Angle), Anchorage Frame,Telescoping Cage Jacking Cage, Tower Crane Yoke, Hook and so on.
Basic Mast Section,Tower Crane Mast,Crane Mast Section,Tower Crane Mast Section,Tower Crane Basic Mast SHEN YANG BAOQUAN BUSINESS CO., LTD , https://www.sytoplesstowercrane.com