CN114987610A - Differential steering device of articulated tracked vehicle and control method - Google Patents
Differential steering device of articulated tracked vehicle and control method Download PDFInfo
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- CN114987610A CN114987610A CN202210791442.7A CN202210791442A CN114987610A CN 114987610 A CN114987610 A CN 114987610A CN 202210791442 A CN202210791442 A CN 202210791442A CN 114987610 A CN114987610 A CN 114987610A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
- B62D11/001—Steering non-deflectable wheels; Steering endless tracks or the like control systems
- B62D11/003—Electric or electronic control systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
- B62D11/001—Steering non-deflectable wheels; Steering endless tracks or the like control systems
- B62D11/005—Hydraulic control systems
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D11/00—Steering non-deflectable wheels; Steering endless tracks or the like
- B62D11/02—Steering non-deflectable wheels; Steering endless tracks or the like by differentially driving ground-engaging elements on opposite vehicle sides
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Abstract
The invention relates to a differential steering device and a control method for an articulated tracked vehicle, belonging to the technical field of mechanical engineering. The steering angle sensor and the actual steering angle sensor are electrically connected with a differential controller, the differential controller is electrically connected with a differential steering switching valve, the differential controller receives signals of the steering angle sensor at the position of a steering gear and the actual steering angle sensor at the position of an articulated mechanism, the steering angle sensor detects a steering angle alpha of the steering gear, and the actual steering angle sensor detects actual steering angles beta of a front vehicle and a rear vehicle. The advantages are that: the ground friction resistance during steering can be reduced, the torque requirement of an engine is reduced, and the steering flexibility is improved; the hydraulic system with the differential steering function is provided, and the emergency steering function is added. The oil cylinder passive telescopic limit position is subjected to limit protection control, the steering precision and the response speed are improved, and the safety of the hinge mechanism is ensured.
Description
Technical Field
The invention relates to the technical field of mechanical engineering, in particular to a differential steering device of an articulated tracked vehicle and a control method.
Background
The articulated tracked vehicle comprises a front vehicle, an articulated mechanism and a rear vehicle, wherein a plurality of vehicle bodies are connected in series through the articulated mechanism, and the pose of each vehicle body can be changed in real time according to different terrain conditions, so that each track is better contacted with the ground, and the articulated tracked vehicle has higher all-terrain trafficability. Articulated tracked vehicles steer in a manner different from conventional single track vehicles. The traditional single-section tracked vehicle mainly realizes the steering motion with different radiuses by adjusting the rotating speed of the inner side and the outer side of the tracks. The articulated tracked vehicle changes the pose of the front and rear vehicle bodies by controlling the stretching amount of a left steering oil cylinder and a right steering oil cylinder in an articulated mechanism so as to realize steering movement. In the process, the inner and outer side tracks do not output driving force outwards, and the left and right steering oil cylinders in the hinge mechanism are driving mechanisms. In this case, the vehicle body is a passive bearing body, and a large ground frictional resistance needs to be overcome. Particularly, when the steering wheel is used on a hard road surface, the road surface is damaged, the abrasion of the crawler belt is accelerated, and the service life of the crawler belt is shortened.
The prior electric transmission articulated tracked vehicle comprises an engine 6, a generator 7, an electric control central unit 5, a front vehicle traction motor 12, a rear vehicle traction motor 10, a front vehicle side transmission 9, a rear vehicle side transmission 11, a left steering oil cylinder 16, a right steering oil cylinder 17 and the like, and is shown as a dotted frame in figure 3.
The current mechanically-driven articulated tracked vehicle consists of an engine 18, a gearbox 19, a transfer case 20, an interaxle differential 21, a power differential 8, side drives 22, 24 and the like, as shown in the dashed box in fig. 4.
The crude oil cylinder steering device is mainly executed by a left steering oil cylinder 16 and a right steering oil cylinder 17 in an articulated mechanism, and comprises a pump 13, a priority valve 14, a load sensing steering gear 15, a left steering oil cylinder 16 and a right steering oil cylinder 17, as shown in figures 3 and 4. When steering, the steering gear is operated, the steering gear is connected with a load sensing steering gear 15, the load sensing steering gear 15, a left steering oil cylinder 16 and a right steering oil cylinder 17 form a position control system, and the displacement of piston rods of the left steering oil cylinder 16 and the right steering oil cylinder 17 is in direct proportion to the angular displacement of a valve core of the load sensing steering gear 15. Therefore, in the conventional cylinder steering device, the left steering cylinder 16 and the right steering cylinder 17 actively extend or contract to push the front vehicle or the rear vehicle of the articulated tracked vehicle, so that the front vehicle and the rear vehicle form a steering angle to complete steering, and the default steering mode is the cylinder steering mode consisting of the priority valve 14, the load sensing steering gear 15, the left steering cylinder 16 and the right steering cylinder 17.
Disclosure of Invention
The invention provides a differential steering device and a control method for an articulated tracked vehicle, and aims to reduce ground friction resistance during steering, reduce the torque requirement of an engine and improve the steering flexibility.
The technical scheme includes that the steering gear steering angle control device comprises a steering gear steering angle sensor, an actual steering angle sensor, a differential controller and a differential steering switching valve, wherein the steering gear steering angle sensor and the actual steering angle sensor are electrically connected with the differential controller, the differential controller is electrically connected with the differential steering switching valve, the differential controller receives signals of the steering gear steering angle sensor at the position of a steering gear and the actual steering angle sensor at the position of an articulated mechanism, the steering gear steering angle sensor detects a steering gear steering angle alpha, and the actual steering angle sensor detects actual steering angles beta of front and rear vehicles.
The differential steering apparatus of the present invention further comprises: the differential controller is mechanically connected with the variable pump, the motor and the power differential in sequence.
A method of differential steering control for an articulated tracked vehicle, comprising:
the differential controller calculates a differential value psi, the differential value psi is distributed to two sides of a front vehicle through an electric control central unit or a variable pump through a motor and a power differential to be transmitted, a rotating speed difference of left and right crawler driving wheels is formed, and a differential steering angle is formed; the method comprises the following steps:
(1) the differential controller receives a steering angle signal of a front vehicle steering gear, performs parameter initialization, and converts the steering angle signal of the front vehicle steering gear into a target steering angle signal;
the steering angle sensor 1 detects a steering angle α of the steering gear, and corrects the detected steering angle α to a target steering angle r by the formula (1) in which: alpha is alpha min Is the minimum steering angle of the steering gear, alpha max Is the maximum steering angle of the steering gear; and obtaining a target steering angular velocity delta r;
(2) calculating a differential value psi required by a target steering angle r and a target steering angular velocity delta r by using fuzzy control in consideration of velocity compensation in initial steering and steering return 1 ；
The fuzzy controller is realized by converting a series of fuzzy control rules into a query table (also called a control table) in an off-line manner, and the fuzzy control process comprises the following steps: defining an input and output fuzzy set and a membership function, establishing a fuzzy control rule, performing fuzzy reasoning and defuzzification, wherein the establishment of the fuzzy control rule is the key for realizing characteristic control, and the fuzzy control process comprises the following steps:
1) defining input fuzzy subsets
Defining an input fuzzy subset, r: positive large PL, positive small PS, zero positive Z0+, zero negative Z0-, negative small NS, negative large NL, r taking N as left turn; taking P as right steering, and the discourse domain of r is [ -35, +35 ]; Δ r: positive large PL, positive small PS, zero positive Z0+, zero Z0, negative small NS, negative large NL, and taking N as r deceleration change; taking P as r and accelerating change, wherein the discourse domain of the delta r is [ -35, +35 ];
2) a subset of the output ambiguities is defined,
defining an output fuzzy subset, ψ 1 : positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, ψ 1 Taking N as left steering, psi 1 Taking P as right steering; psi 1 Has a discourse field of [0,80 ]]；
3) Defining a fuzzy rule table:
when r is NL and Δ r is NL, /) 1 Is PL;
when r is NS and Δ r is NL, # 1 Is PS;
when r is Z0-and Δ r is NL, # 1 Is PS;
when r is Z0+ and Δ r is NL,. psi 1 Is NS;
when r is PS and Δ r is NL, # 1 Is NS;
when r is PL and Δ r is NL, # 1 NL;
when r is NL and Δ r is NS,/[ phi ] 1 Is PS;
when r is NS and Δ r is NS, # 1 Is Z0;
when r is Z0-and Δ r is NS,. psi 1 Is Z0;
when r is Z0+ and Δ r is NS,. phi. 1 Is Z0;
when r is PS and Δ r is NS,. psi 1 Is Z0;
when r is PL and Δ r is NS,. psi 1 Is NS;
when r is NL and Δ r is Z0, ψ 1 NL;
when r is NS and Δ r is Z0, ψ 1 Is NS;
when r is Z0-and Δ r is Z0, ψ 1 Is Z0;
when r is Z0+ and Δ r is Z0,. psi 1 Is Z0;
when r is PS and Δ r is Z0 1 Is PS;
when r is PL and Δ r is Z0, # 1 Is PL;
when r is NL and Δ r is PS,. psi 1 NL;
when r is NS and Δ r is PS,. psi 1 Is NS;
when r is Z0-and Δ r is PS,. phi. 1 Is Z0;
when r is Z0+ and Δ r is PS,. phi. 1 Is PS;
when r is PS and Δ r is PS, ψ 1 Is PS;
when r is PL and Δ r is PS,. phi 1 Is PL;
when r is NL and Δ r is PL 1 NL;
when r is NS and Δ r is PL, ψ 1 NL;
when r is Z0-and Δ r is PL,. phi. 1 Is NS;
when r is Z0+ and Δ r is PL,. phi. 1 Is PL;
when r is PS and Δ r is PL,. phi 1 Is PL; when r is PL and Δ r is PL, # 1 Is PL.
4) The input quantities r, Δ r and the output quantity ψ 1 Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) performing defuzzification by adopting a maximum membership method;
(3) actual steering angle sensors 2 mounted on the front and rear vehicle hinge mechanisms detect actual steering angles beta of the front and rear vehicles, a steering angle deviation e is r-beta, a deviation variation delta e is obtained, differential compensation of the actual steering angle relative to a target steering angle response lag is considered, and a differential compensation value psi required by the steering angle deviation e and the deviation variation delta e is calculated by fuzzy control 2 ；
1) Defining input fuzzy subsets
ψ 2 left side Difference velocity compensation value psi for left steering 2 ；ψ 2 right side Differential compensation value psi for right steering 2 ；
Defining an input fuzzy subset, e: positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, taking N as over-steering and taking P as under-steering; e has a discourse field of [ -35, +35 ]; Δ e: positive large PL, positive small PS, zero Z0, negative small NS, NL negative large, taking N as e deceleration change, taking P as e acceleration change, and taking argument of [ 35, +35 ];
2) defining output fuzzy subsets
Defining an output fuzzy subset, ψ 2 : positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, ψ 2 Taking N as left turn, psi 2 Let P be right-hand, psi 2 Has a discourse field of [0,80 ]]；
3) Defining fuzzy rule tables
When e is NL and Δ e is NL, # 2 left side Is PL, psi 2 right side NL;
when e is NS and Δ e is NL, # 2 left Is PL, psi 2 right side NL;
when e is Z0 and Δ e is NL, # 2 left side Is PS, psi 2 right side Is NS;
when e is PS and Δ e is NL, # 2 left Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NL, # 2 left side Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is NS,. psi 2 left side Is PL, psi 2 right side NL;
when e is NS and Δ e is NS, ψ 2 left side Is PS, psi 2 right side Is PS;
when e is Z0 and Δ e is NS, ψ 2 left Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is NS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NS,. psi 2 left Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is Z0 2 left side Is PS, psi 2 right side Is NS;
when e is NS and Δ e is Z0, ψ 2 left side Is PS, psi 2 right side Is NS;
when e is Z0 and Δ e is Z0, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is Z0, ψ 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is Z0, # 2 left side Is NS, psi 2 right side Is PS;
when e is NL and Δ e is PS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NS and Δ e is PS, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is PS,. psi 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is PS,. psi 2 left side Is NL, ψ 2 right side Is PL;
when e is NL and Δ e is PL,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NS and Δ e is PL, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PL 2 left side Is NS, psi 2 right side Is PS;
when e is PS and Δ e is PLWhen, psi 2 left side Is NL, ψ 2 right side Is PL;
when e is PL and Δ e is PL, # 2 left side Is NL, ψ 2 right side Is PL;
4) the input quantities e, Δ e and the output quantity ψ 2 left 、ψ 2 right side Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) defuzzification is carried out by adopting a maximum membership method;
(4) differential value psi of psi 1 、ψ 2 Computing integration, the expression is as follows:
ψ＝k 1 ψ 1 +k 2 ψ 2 (2)
in the formula k 1 、k 2 As coefficients, when left-hand steering, psi 2 Taking psi 2 left When steering left, psi 2 Taking psi 2 right side ；
(5) Forming a differential steering angle
1) For the electric transmission articulated tracked vehicle, the differential controller 3 outputs a differential value psi signal to the electric control central unit 5, the electric control central unit 5 adjusts the rotating speed of the traction motors 12 on the left side and the right side according to the differential value, so that the rotating speed of the driving wheel on one side is increased, the rotating speed of the driving wheel on the other side is reduced, and a differential steering angle is formed;
2) for the mechanical transmission articulated tracked vehicle, the differential controller 3 outputs a differential value signal to adjust the variable pump 6, the variable pump 6 drives the motor 7 to adjust the differential value of the power differential mechanism 8, and then the rotating speed of one side of the driving wheel is increased, the rotating speed of the other side of the driving wheel is reduced, and a differential steering angle is formed.
The differential controller performs stroke protection on the left steering oil cylinder and the right steering oil cylinder of the hinge mechanism, and prevents the left steering oil cylinder and the right steering oil cylinder from being damaged due to the fact that a steering angle is out of limit;
(1) the differential controller calculates travel limit values of the left steering oil cylinder and the right steering oil cylinder;
when the actual steering angle is close to the maximum steering angle set by the strokes of the left steering oil cylinder and the right steering oil cylinder, stopping steering and recovering the previous constant speed state; in order to prevent the left steering oil cylinder and the right steering oil cylinder from overloading during differential steering, the extension and the shortening of the left steering oil cylinder and the right steering oil cylinder are limited during the differential steering, and the oil cylinders are limited and protected;
the relation between the elongation and the shortening of the left steering oil cylinder and the right steering oil cylinder and the actual steering angle beta is shown in a formula (3), and the maximum elongation and the shortening of the left steering oil cylinder and the right steering oil cylinder under the set maximum steering angle are calculated according to the formula (3);
in the formula:
a, the distance from a front vehicle connecting point A to a hinge point O, and a fixed value is designed for a hinge mechanism;
b, the distance from the rear vehicle connecting point B to the hinge point O, and a fixed value is designed for the hinge mechanism;
c, the distance from the rear vehicle connecting point C to the hinge point O is a fixed value designed for the hinge mechanism;
d is the distance from the front vehicle connecting point D to the hinge point O, and a fixed value is designed for the hinge mechanism;
α 1 the included angle between a and b is a fixed value designed for the hinge mechanism;
α 2 the included angle between c and d is a fixed value designed for the hinge mechanism;
l 10 -the shortening of the cylinder on one side,
l 20 -the extension of the cylinder on the other side,
β — actual steering angle;
(2) detecting an actual steering angle beta, and converting the actual steering angle beta into the elongation or shortening of the left steering oil cylinder and the right steering oil cylinder according to a formula (3);
(3) if the extension or the shortening of the left steering oil cylinder and the right steering oil cylinder reaches a stroke value, limiting protection is implemented, differential steering is stopped, and the steering angle is kept not to be increased any more.
The invention has the beneficial effects that:
the differential steering device is provided for the articulated tracked vehicle, the idea of replacing oil cylinder steering with differential steering can reduce ground friction resistance during steering, reduce the torque requirement of an engine and improve the steering flexibility; the hydraulic system with the differential steering function is provided, the differential steering mode is added to the hydraulic system on the basis of the original oil cylinder steering mode, a vehicle can be switched between the oil cylinder steering mode and the differential steering mode, and the emergency steering function is added.
By adopting a differential steering control method, a differential controller carries out differential value calculation according to received target steering angle, target steering angle increment, vehicle speed, actual steering angle and actual steering angle increment signals, the speed compensation of initial steering and steering return is considered in the differential value calculation, differential compensation is carried out on the difference between the actual steering angle and the target steering angle, and the steering precision and the response speed are improved; in addition, the oil cylinder passive telescopic limit position is subjected to limit protection control. The control system makes full use of the large-radius steering range, has steering safety, improves the steering precision and response speed, and ensures the safety of the hinge mechanism. The differential steering control method is also suitable for the steering working condition when two tracked vehicles are spliced to execute emergency rescue or improve the trafficability characteristic of a wide trench.
Drawings
FIG. 1 is a schematic view of a differential steering apparatus for an electric drive articulated tracked vehicle;
FIG. 2 is a schematic view of a differential steering apparatus for a mechanically driven articulated tracked vehicle;
FIG. 3 is a diagram of an electric drive articulated tracked vehicle differential steering system application; wherein, a thick solid line frame is a differential steering device, a thin solid line is an electric control transmission path, and a steering gear angle sensor 1 and an actual angle sensor 2 are electrically connected with a differential controller 3, a differential steering switching valve 4 and an electric control central control unit 5; the thick solid line is a transmission path of a hydraulic system, the differential steering switching valve 4 is in hydraulic connection with the left steering oil cylinder 16 and the right steering oil cylinder 17, the thin dotted line is a mechanical power transmission path, the engine 6, the generator 7, the electric control central unit 5, the traction motor 12 and the side transmission 9 are in mechanical connection, and the traction motor 10 is in mechanical connection with the side transmission 11; the thin-dotted lines are transmission paths of an electric system, and the electric control central unit 5 and the traction motor 10 are electrically connected; the chain double-dashed line is a hydraulic system transmission path, and the pump 13 is connected with the differential steering switching valve 4 through a hydraulic system; the dotted line is a hydraulic power path of the existing oil cylinder steering device, and the pump 13, the priority valve 14 and the load sensing steering gear 15 are hydraulically connected with the left steering oil cylinder 16 and the right steering oil cylinder 17;
FIG. 4 is a differential steering system application diagram for a mechanically driven articulated tracked vehicle; the thick solid line frame is a differential steering device, the thin solid line is an electric control transmission path, the steering gear angle sensor 1 and the actual angle sensor 2 are electrically connected with the differential controller 3 and the steering switching valve 4, the thick solid line is a hydraulic system and mechanical power transmission path, the differential controller 3, the variable pump 6, the motor 7 and the power differential 8 are mechanically connected, and the differential steering switching valve 4 is hydraulically connected with the left steering oil cylinder 16 and the right steering oil cylinder 17; the thin dotted line is a mechanical power transmission path, the engine 18, the gearbox 19, the transfer case 21, the interaxial differential 20, the power differential 8 and the side transmission 22 are mechanically connected, the engine 18, the gearbox 19, the transfer case 21, the interaxial differential 21, the differential 23 and the side transmission 24 are mechanically connected, and the variable pump 6, the transfer case 20 and the pump 13 are mechanically connected; the chain double-dashed line is a hydraulic system transmission path, and the pump 13 is connected with the differential steering switching valve 4 through a hydraulic system; the dotted line is a hydraulic power path of the existing oil cylinder steering device, and the pump 13, the priority valve 14 and the load sensing steering gear 15 are hydraulically connected with the left steering oil cylinder 16 and the right steering oil cylinder 17;
FIG. 5 is a differential steering control schematic;
FIG. 6 is a vehicle speed-steering radius relationship diagram;
FIG. 7 is a steering schematic of the track-type articulation mechanism.
Detailed Description
For an electric tracked articulated vehicle, as shown in fig. 1, comprising: the steering gear steering angle sensor comprises a steering gear steering angle sensor 1, an actual steering angle sensor 2, a differential controller 3 and a differential steering switching valve 4, wherein the steering gear steering angle sensor 1 and the actual steering angle sensor 2 are electrically connected with the differential controller 3, the differential controller 3 is electrically connected with the differential steering switching valve 4, the differential controller 3 receives signals of the steering gear steering angle sensor 1 at the position of a steering gear and the actual steering angle sensor 2 at the position of an articulated mechanism, the steering gear steering angle sensor 1 detects a steering gear steering angle alpha, and the actual steering angle sensor 2 detects actual steering angles beta of front and rear vehicles.
For a mechanically driven track-type articulated vehicle, as shown in fig. 2, the differential steering apparatus further comprises: the variable displacement pump 6, the motor 7 and the power differential 8, wherein the differential controller 3 is sequentially and mechanically connected with the variable displacement pump 6, the motor and the power differential 8.
The present invention will be further explained below by way of an application example of a differential steering device.
The invention can be reformed and implemented on the electric transmission articulated tracked vehicle based on the oil cylinder steering, and because the electric transmission articulated tracked vehicle independently adjusts the left side transmission 9 and the right side transmission 9 by adopting the traction motor 12, the differential steering device and the control method can be conveniently implemented on the electric transmission articulated tracked vehicle. The specific modification content comprises the following steps: the device comprises a steering angle sensor 1, an actual steering angle sensor 2, a differential controller 3, a differential steering switching valve 4 and the like. Similarly, the method can be implemented on a mechanical transmission articulated tracked vehicle based on cylinder steering, and the specific modification content comprises the following steps: the device comprises a steering angle sensor 1, an actual steering angle sensor 2, a differential controller 3, a differential steering switching valve 4, a variable pump 6, a motor 7, a power differential 8 and the like.
Example 1, referring to fig. 3, for an electric-transmission articulated tracked vehicle, a differential controller 3 is adopted to receive a steering angle signal of a steering gear of a front vehicle, and according to a vehicle speed state and a converted target steering radius, the differential controller 3 outputs a differential value signal to an electric control central unit 5 of the electric-transmission tracked vehicle, the electric control central unit 5 adjusts the rotating speed of a left front traction motor 12 and a right front traction motor 12 according to the differential value, so that the rotating speed of a driving wheel on one side is increased, the rotating speed of a driving wheel on the other side is reduced, and a steering angle is formed; at this time, the left steering cylinder 16 and the right steering cylinder 17 are in a passive extension and contraction state, the left steering cylinder 16 and the right steering cylinder 17 are designed to be in a floating state, a rod cavity of the left steering cylinder 16 is connected with a rodless cavity of the right steering cylinder 17, the rodless cavity of the left steering cylinder 16 is connected with a rod cavity of the right steering cylinder 17, so that the left steering cylinder 16 and the right steering cylinder 17 form a self-communicating loop, and when the differential steering switching valve 4 is powered, the cylinder steering mode can be switched to the differential steering mode through the differential steering switching valve 4; in addition, the differential controller 3 receives the signal of the actual turning angle sensor 2 at the hinge mechanism, and compensates and corrects the difference between the target steering angle and the actual steering angle; meanwhile, the differential controller 3 performs stroke protection on the extension and contraction of the left steering oil cylinder 16 and the right steering oil cylinder 17 of the hinge mechanism, and prevents the oil cylinders from being damaged due to the fact that the steering angle is out of limit.
Example 2, referring to fig. 4, for the mechanical transmission articulated tracked vehicle, the differential controller 3 is adopted to receive a steering angle signal of a steering device of a front vehicle, and output a differential value signal to adjust the variable pump 6 according to the vehicle speed state and the converted target steering radius, and then the motor 7 adjusts the differential value of the power differential 8, so that the rotating speed of one driving wheel is increased, the rotating speed of the other driving wheel is reduced, and a steering angle is formed. At this time, the left steering cylinder 16 and the right steering cylinder 17 are in a passive extension and contraction state, the left steering cylinder 16 and the right steering cylinder 17 are designed to be in a floating state, a rod chamber of the left steering cylinder 16 is connected with a rod chamber of the right steering cylinder 17, and the rod chamber of the left steering cylinder 16 is connected with a rod chamber of the right steering cylinder 17, so that the left steering cylinder 16 and the right steering cylinder 17 form a self-communicating loop, and when the differential steering switching valve 4 is powered, the cylinder steering mode can be switched to the differential steering mode through the differential steering switching valve 4. In addition, the differential controller 3 receives the signal of the actual corner sensor 2 at the position of the hinge mechanism, compensates and corrects the difference between the target corner and the actual corner, and simultaneously, the differential controller 3 executes the stroke protection of the extension and retraction of the left steering oil cylinder 16 and the right steering oil cylinder 17 of the hinge mechanism, thereby preventing the oil cylinders from being damaged due to the over-limit of the steering angle.
Referring to fig. 5, a differential steering control method for an articulated tracked vehicle comprises:
the differential controller 3 calculates a differential value psi, the differential value psi is distributed to two sides of a front vehicle for transmission through an electric control central unit 5 or a variable pump 6 through a motor 7 and a power differential 8 to form a rotating speed difference between left and right crawler driving wheels and a differential steering angle; the method comprises the following steps:
(1) the differential controller 3 receives the steering angle signal of the steering gear of the front vehicle, initializes parameters and converts the steering angle signal of the steering gear of the front vehicle into a target steering angle signal;
the steering angle sensor 1 detects a steering angle α of the steering gear, and corrects the detected steering angle α to a target steering angle r by the formula (1) in which: alpha is alpha min Is the minimum steering angle of the steering gear, alpha max Is the maximum steering angle of the steering gear; and obtaining a target steering angular velocity delta r;
(2) calculating a differential value psi required by a target steering angle r and a target steering angular velocity delta r by using fuzzy control in consideration of velocity compensation in initial steering and steering return 1 ；
The fuzzy controller is realized by converting a series of fuzzy control rules into a query table (also called control table) in an off-line manner, and the fuzzy control process comprises the following steps: defining an input and output fuzzy set and a membership function, establishing a fuzzy control rule, performing fuzzy reasoning and defuzzification, wherein the establishment of the fuzzy control rule is the key for realizing characteristic control, and the fuzzy control process comprises the following steps:
1) defining input fuzzy subsets
Defining an input fuzzy subset, r: positive large PL, positive small PS, zero positive Z0+, zero negative Z0-, negative small NS, negative large NL, r taking N as left turn; taking P as right steering, and the discourse domain of r is [ -35, +35 ]; Δ r: positive large PL, positive small PS, zero positive Z0+, zero Z0, negative small NS, negative large NL, and taking N as r deceleration change; taking P as r and accelerating change, wherein the discourse domain of the delta r is [ -35, +35 ];
2) a subset of the output ambiguities is defined,
defining an output fuzzy subset, ψ 1 : positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, ψ 1 Taking N as left turn, psi 1 Taking P as right steering; psi 1 Has a discourse field of [0,80 ]]；
3) Defining a fuzzy rule table 1;
TABLE 1 psi 1 Fuzzy rule table
When r is NL and Δ r is NL, # 1 Is PL;
when r is NS and Δ r is NL, # 1 Is PS;
when r is Z0-and Δ r is NL, # 1 Is PS;
when r is Z0+ and Δ r is NL,. phi. 1 Is NS;
when r is PS and Δ r is NL,. psi 1 Is NS;
when r is PL and Δ r is NL, # 1 NL;
when r is NL and Δ r is NS,. psi 1 Is PS;
when r is NS and Δ r is NS, ψ 1 Is Z0;
when r is Z0-and Δ r is NS,. psi 1 Is Z0;
when r is Z0+ and Δ r is NS,. phi. 1 Is Z0;
when r is PS and Δ r is NS,. psi 1 Is Z0;
when r is PL and Δ r is NS,. psi 1 Is NS;
when r is NL and Δ r is Z0, ψ 1 NL;
when r is NS and Δ r is Z0, ψ 1 Is NS;
when r is Z0-and Δ r is Z0 1 Is Z0;
when r is Z0+ and Δ r is Z0,. psi 1 Is Z0;
when r is PS and Δ r is Z0, # 1 Is PS;
when r is PL and Δ r is Z0 1 Is PL;
when r is NL and Δ r is PS,. psi 1 NL;
when r is NS and Δ r is PS,. psi 1 Is NS;
when r is Z0-and Δ r is PS,. phi 1 Is Z0；
When r is Z0+ and Δ r is PS,. phi. 1 Is PS;
when r is PS and Δ r is PS,. phi 1 Is PS;
when r is PL and Δ r is PS,. phi 1 Is PL;
when r is NL and Δ r is PL, # 1 NL;
when r is NS and Δ r is PL, ψ 1 NL;
when r is Z0-and Δ r is PL,. phi. 1 Is NS;
when r is Z0+ and Δ r is PL,. phi. 1 Is PL;
when r is PS and Δ r is PL,. psi 1 Is PL;
when r is PL and Δ r is PL, # 1 Is PL.
4) The input quantities r, Δ r and the output quantity ψ 1 Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) performing defuzzification by adopting a maximum membership method;
(3) actual steering angle sensors 2 mounted on the front and rear vehicle hinge mechanisms detect actual steering angles beta of the front and rear vehicles, a steering angle deviation e is r-beta, a deviation variation delta e is obtained, differential compensation of the actual steering angle relative to a target steering angle response lag is considered, and a differential compensation value psi required by the steering angle deviation e and the deviation variation delta e is calculated by fuzzy control 2 ；
1) Defining input fuzzy subsets
ψ 2 left side Difference velocity compensation value psi for left steering 2 ；ψ 2 right side Differential compensation value psi for right steering 2 ；
Defining an input fuzzy subset, e: positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, taking N as over-steering and taking P as under-steering; e has a discourse field of [ -35, +35 ]; Δ e: positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, N is the deceleration change of E for N, the acceleration change of E for P for E for Delta e, and the discourse domain of Delta e is [ -35, +35 ];
2) defining output fuzzy subsets
Defining an output fuzzy subset, ψ 2 : positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, ψ 2 Taking N as left turn, psi 2 Taking P as right turn, psi 2 Has a discourse field of [0,80 ]]；
3) Defining a fuzzy rule table 2;
TABLE 2 psi 2 left side ，ψ 2 right side Fuzzy rule table
Note: in table the upper behavior psi 2 left Differential compensation value of phi 2 right side The differential compensation value of (1).
When e is NL and Δ e is NL, # 2 left side Is PL, ψ 2 right side NL;
when e is NS and Δ e is NL, # 2 left side Is PL, ψ 2 right side NL;
when e is Z0 and Δ e is NL, # 2 left side Is PS, psi 2 right side Is NS;
when e is PS and Δ e is NL, ψ 2 left Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NL,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is NS,. psi 2 left side Is PL, psi 2 right side NL;
when e is NS and Δ e is NS, ψ 2 left side Is PS, psi 2 right side Is PS;
when e is Z0 and Δ e is NS, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is NS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is Z0, ψ 2 left side Is PS, psi 2 right side Is NS;
when e is NS and Δ e is Z0, ψ 2 left side Is PS, psi 2 right side Is NS;
when e is Z0 and Δ e is Z0, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is Z0, ψ 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is Z0, # 2 left side Is NS, psi 2 right side Is PS;
when e is NL and Δ e is PS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NS and Δ e is PS, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is PS,. psi 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is PS,. psi 2 left Is NL, ψ 2 right side Is PL;
when e is NL and Δ e is PL, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is NS and Δ e is PL, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PL 2 left side Is NS, psi 2 right side Is PS;
when e is PS and Δ e is PL,. phi 2 left side Is NL, ψ 2 right side Is PL;
when e is PL and Δ e is PL, ψ 2 left side Is NL, ψ 2 right side Is PL;
4) the input quantities e, Δ e and the output quantity ψ 2 left side 、ψ 2 right side Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) performing defuzzification by adopting a maximum membership method;
(4) differential value psi of psi 1 、ψ 2 Set of calculationsThen, a differential value signal psi is output according to the vehicle speed state, the relation between the relative steering radius 1/r and the vehicle speed v is defined as shown in FIG. 6, the relative steering radius is the reciprocal of the steering angle, when the vehicle speed is smaller, the relative steering radius can be smaller, and the steering angle can be larger; when the vehicle speed is large, the steering radius can only be large, the steering angle can only be small, and after the steering angle constrained by the vehicle speed is determined, the differential value psi is expressed as follows:
ψ＝k 1 ψ 1 +k 2 ψ 2 (2)
in the formula k 1 、k 2 As coefficients, when left-hand steering, psi 2 Taking psi 2 left side When steering left, psi 2 Psi extraction 2 right side ；
(5) Forming a differential steering angle
1) For the electric transmission articulated tracked vehicle, the differential controller 3 outputs a differential value psi signal to the electric control central unit 5, the electric control central unit 5 adjusts the rotating speed of the traction motors 12 on the left side and the right side according to the differential value, so that the rotating speed of the driving wheel on one side is increased, the rotating speed of the driving wheel on the other side is reduced, and a differential steering angle is formed;
2) for the mechanical transmission articulated tracked vehicle, the differential controller 3 outputs a differential value signal to adjust the variable pump 6, the variable pump 6 drives the motor 7 to adjust the differential value of the power differential mechanism 8, and then the rotating speed of one side of the driving wheel is increased, the rotating speed of the other side of the driving wheel is reduced, and a differential steering angle is formed.
The differential controller 3 performs stroke protection on the left steering oil cylinder 16 and the right steering oil cylinder 17 of the hinge mechanism, and prevents the left steering oil cylinder 16 and the right steering oil cylinder 17 from being damaged due to the fact that a steering angle is out of limit;
(1) the differential controller 3 calculates the travel limit values of the left steering oil cylinder 16 and the right steering oil cylinder 17;
when the actual steering angle is close to the maximum steering angle set by the strokes of the left steering oil cylinder 16 and the right steering oil cylinder 17, stopping steering and recovering the previous constant speed state; in order to prevent the left steering oil cylinder 16 and the right steering oil cylinder 17 from overloading during differential steering, the extension and the shortening of the left steering oil cylinder 16 and the right steering oil cylinder 17 are limited during the differential steering, and the oil cylinders are limited and protected;
the principle of calculating the maximum extension and contraction amounts of the left steering cylinder 16 and the right steering cylinder 17 is shown in fig. 7, wherein a dotted line is the original position of the hinge mechanism, a solid line is the position of the hinge mechanism after steering, the relation between the extension and contraction amounts of the left steering cylinder 16 and the right steering cylinder 17 and the actual steering angle beta is shown in a formula (3), and the maximum extension and contraction amounts of the left steering cylinder 16 and the right steering cylinder 17 under the set maximum steering angle are calculated according to the formula (3);
in the formula:
a, the distance from a front vehicle connecting point A to a hinge point O, and a fixed value is designed for a hinge mechanism;
b, the distance from the rear vehicle connecting point B to the hinge point O, and a fixed value is designed for the hinge mechanism;
c, the distance from the rear vehicle connecting point C to the hinge point O, and a fixed value is designed for the hinge mechanism;
d is the distance from the front vehicle connecting point D to the hinge point O, and a fixed value is designed for the hinge mechanism;
α 1 the included angle between a and b is a fixed value designed for the hinge mechanism;
α 2 the included angle between c and d is a fixed value designed for the hinge mechanism;
l 10 -the shortening of the cylinder on one side,
l 20 -the amount of elongation of the cylinder on the other side,
β — actual steering angle;
(2) detecting an actual steering angle beta, and converting the actual steering angle beta into an elongation or shortening of the left steering oil cylinder 16 and the right steering oil cylinder 17 according to a formula (3);
(3) if the extension or shortening of the left steering oil cylinder 16 and the right steering oil cylinder 17 reaches the travel value, limiting protection is implemented, differential steering is stopped, and the steering angle is kept not to be increased.
The invention can be provided with two modes of oil cylinder steering and differential steering, and is switched by the differential steering switching valve 4 so as to meet the requirement of a complex road surface and be used as an emergency steering function reserve. When the differential steering switching valve 4 is not powered, the articulated tracked vehicle executes the original oil cylinder steering mode; when the differential steering switching valve 4 is energized, the steering mode is switched to the differential steering mode, and the left steering cylinder 16 and the right steering cylinder 17 in the articulated mechanism are changed into a floating form so as to respond to the passive extension and contraction of the left steering cylinder 16 and the right steering cylinder 17 caused by the differential change. The differential steering mode of the front vehicle and the rear vehicle can reduce the steering resistance to the maximum extent and reduce the slippage and the slip rate of the crawler. When the original steering device breaks down, the differential steering can be used as an emergency steering mode. The differential steering device and the control method are suitable for electric transmission articulated tracked vehicles and mechanical transmission articulated tracked vehicles, and can also be applied to a steering mode after two tracked vehicles are spliced to execute emergency rescue or improve the trafficability of wide trenches.
Claims (3)
1. An articulated tracked vehicle differential steering device which characterized in that: the steering gear steering angle sensor and the actual steering angle sensor are electrically connected with the differential controller, the differential controller is electrically connected with the differential steering switching valve, the differential controller receives signals of the steering gear steering angle sensor at the position of the steering gear and the actual steering angle sensor at the position of the hinge mechanism, the steering gear steering angle sensor detects a steering gear steering angle alpha, and the actual steering angle sensor detects an actual steering angle beta of a front vehicle and a rear vehicle.
2. The differential steering apparatus of an articulated tracked vehicle as defined in claim 1, wherein: the differential steering apparatus further includes: the differential controller is mechanically connected with the variable pump, the motor and the power differential in sequence.
3. A control method using an articulated tracked vehicle differential steering apparatus according to claim 1 or 2, comprising:
the differential controller calculates a differential value psi, the differential value psi is distributed to two sides of a front vehicle through an electric control central unit or a variable pump through a motor and a power differential to be transmitted, a rotating speed difference of left and right crawler driving wheels is formed, and a differential steering angle is formed; the method comprises the following steps:
(1) the differential controller receives a steering angle signal of a front vehicle steering device, performs parameter initialization, and converts the steering angle signal of the front vehicle steering device into a target steering angle signal;
the steering angle sensor 1 detects a steering angle α of a steering gear, and corrects the detected steering angle α to a target steering angle r by the formula (1), in which: alpha (alpha) ("alpha") min Is the minimum steering angle of the steering gear, alpha max Is the maximum steering angle of the steering gear; and obtaining a target steering angular velocity delta r;
(2) calculating a differential value psi required by a target steering angle r and a target steering angular velocity delta r by using fuzzy control in consideration of velocity compensation in initial steering and steering return 1 ；
The fuzzy controller is realized by converting a series of fuzzy control rules into a query table (also called control table) in an off-line manner, and the fuzzy control process comprises the following steps: defining an input and output fuzzy set and a membership function, establishing a fuzzy control rule, performing fuzzy reasoning and defuzzification, wherein the establishment of the fuzzy control rule is the key for realizing characteristic control, and the fuzzy control process comprises the following steps:
1) defining input fuzzy subsets
Defining an input fuzzy subset, r: positive large PL, positive small PS, zero positive Z0+, zero negative Z0-, negative small NS, negative large NL, r taking N as left turn; taking P as right steering, and the discourse domain of r is [ -35, +35 ]; Δ r: positive large PL, positive small PS, zero positive Z0+, zero Z0, negative small NS, negative large NL, and taking N as r deceleration change; taking P as r and accelerating change, wherein the discourse domain of the delta r is [ -35, +35 ];
2) a subset of the output ambiguities is defined,
defining an output fuzzy subset, ψ 1 : positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, ψ 1 Taking N as left turn, psi 1 Taking P as a right steering direction; psi 1 Has a discourse field of [0,80 ]]；
3) Defining a fuzzy rule table:
when r is NL and Δ r is NL, # 1 Is PL;
when r is NS and Δ r is NL, # 1 Is PS;
when r is Z0-and Δ r is NL, # 1 Is PS;
when r is Z0+ and Δ r is NL,. phi. 1 Is NS;
when r is PS and Δ r is NL, # 1 Is NS;
when r is PL and Δ r is NL, # 1 NL;
when r is NL and Δ r is NS,. psi 1 Is PS;
when r is NS and Δ r is NS, ψ 1 Is Z0;
when r is Z0-and Δ r is NS,. psi 1 Is Z0;
when r is Z0+ and Δ r is NS,. phi. 1 Is Z0;
when r is PS and Δ r is NS,. psi 1 Is Z0;
when r is PL and Δ r is NS,. psi 1 Is NS;
when r is NL and Δ r is Z0 1 NL;
when r is NS and Δ r is Z0, ψ 1 Is NS;
when r is Z0-and Δ r is Z0, ψ 1 Is Z0;
when r is Z0+ and Δ r is Z0,. psi 1 Is Z0;
when r is PS and Δ r is Z0, # 1 Is PS;
when r is PL and Δ r is Z0, # 1 Is PL;
when r is NL and Δ r is PS,. psi 1 NL;
when r is NS and Δ r is PS, ψ 1 Is NS;
when r is Z0-and Δ r is PS,. phi. 1 Is Z0;
when r is Z0+ and Δ r is PS,. phi. 1 Is PS;
when r is PS and Δ r is PS,. phi 1 Is PS;
when r is PL and Δ r is PS,. phi 1 Is PL;
when r is NL and Δ r is PL, # 1 NL;
when r is NS and Δ r is PL, ψ 1 NL;
when r is Z0-and Δ r is PL 1 Is NS;
when r is Z0+ and Δ r is PL,. phi. 1 Is PL;
when r is PS and Δ r is PL,. phi 1 Is PL;
when r is PL and Δ r is PL,. psi 1 Is PL.
4) The input quantities r, Δ r and the output quantity ψ 1 Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) performing defuzzification by adopting a maximum membership method;
(3) actual steering angle sensors 2 mounted on the front and rear vehicle hinge mechanisms detect actual steering angles beta of the front and rear vehicles, a steering angle deviation e is r-beta, a deviation variation delta e is obtained, differential compensation of the actual steering angle relative to a target steering angle response lag is considered, and a differential compensation value psi required by the steering angle deviation e and the deviation variation delta e is calculated by fuzzy control 2 ；
1) Defining input fuzzy subsets
ψ 2 left Difference velocity compensation value psi for left steering 2 ；ψ 2 right side Differential compensation value psi for right steering 2 ；
Defining an input fuzzy subset, e: positive large PL, positive small PS, zero Z0, negative small NS, negative large NL, taking N as over-steering and taking P as under-steering; e has a discourse field of [ -35, +35 ]; Δ e: positive large PL, positive small PS, zero Z0, negative small NS, NL negative large, taking N as e deceleration change, taking P as e acceleration change, and taking argument of [ 35, +35 ];
2) defining output fuzzy subsets
Defining an output fuzzy subset, ψ 2 : positive large PL, positiveSmall PS, zero Z0, negative small NS, negative large NL, ψ 2 Taking N as left turn, psi 2 Taking P as right turn, psi 2 Has a discourse field of [0,80 ]]；
3) Defining fuzzy rule tables
When e is NL and Δ e is NL, # 2 left side Is PL, psi 2 right side NL;
when e is NS and Δ e is NL, # 2 left side Is PL, ψ 2 right side NL;
when e is Z0 and Δ e is NL, # 2 left side Is PS, psi 2 right side Is NS;
when e is PS and Δ e is NL, # 2 left side Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NL, # 2 left side Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is NS,. psi 2 left Is PL, psi 2 right side NL;
when e is NS and Δ e is NS, ψ 2 left side Is PS, psi 2 right side Is PS;
when e is Z0 and Δ e is NS, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is NS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PL and Δ e is NS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NL and Δ e is Z0, ψ 2 left side Is PS, psi 2 right side Is NS;
when e is NS and Δ e is Z0, ψ 2 left side Is PS, psi 2 right side Is NS;
when e is Z0 and Δ e is Z0, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is Z0, ψ 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is Z0, # 2 left side Is NS, psi 2 right side Is PS;
when e is NL and Δ e is PS,. psi 2 left Is Z0, psi 2 right side Is Z0;
when the e is the number of the NS,and Δ e is PS, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PS,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is PS and Δ e is PS,. psi 2 left side Is NS, psi 2 right side Is PS;
when e is PL and Δ e is PS,. psi 2 left side Is NL, ψ 2 right side Is PL;
when e is NL and Δ e is PL,. psi 2 left side Is Z0, psi 2 right side Is Z0;
when e is NS and Δ e is PL, ψ 2 left side Is Z0, psi 2 right side Is Z0;
when e is Z0 and Δ e is PL 2 left side Is NS, psi 2 right side Is PS;
when e is PS and Δ e is PL,. phi 2 left side Is NL, ψ 2 right side Is PL;
when e is PL and Δ e is PL, # 2 left side Is NL, ψ 2 right side Is PL;
4) the input quantities e, Δ e and the output quantity ψ 2 left side 、ψ 2 right side Adopting triangular membership functions, and fuzzifying the functions in respective discourse space;
5) carrying out fuzzy reasoning by adopting a Mamdali fuzzy reasoning method;
6) performing defuzzification by adopting a maximum membership method;
(4) differential value psi is set from psi 1 、ψ 2 Computing integration, the expression is as follows:
ψ＝k 1 ψ 1 +k 2 ψ 2 (2)
in the formula k 1 、k 2 As coefficients, when left-hand steering, psi 2 Taking psi 2 left When steering left, psi 2 Taking psi 2 right side ；
(5) Forming a differential steering angle
1) For the electric transmission articulated tracked vehicle, the differential controller 3 outputs a differential value psi signal to the electric control central unit 5, the electric control central unit 5 adjusts the rotating speed of the traction motors 12 on the left side and the right side according to the differential value, so that the rotating speed of the driving wheel on one side is increased, the rotating speed of the driving wheel on the other side is reduced, and a differential steering angle is formed;
2) for the mechanical transmission articulated tracked vehicle, the differential controller 3 outputs a differential value signal to adjust the variable pump 6, the variable pump 6 drives the motor 7 to adjust the differential value of the power differential mechanism 8, and then the rotating speed of one side of the driving wheel is increased, and the rotating speed of the other side of the driving wheel is reduced to form a differential steering angle.
The differential controller performs stroke protection on the left steering oil cylinder and the right steering oil cylinder of the hinge mechanism, and prevents the left steering oil cylinder and the right steering oil cylinder from being damaged due to over-limit of a steering angle;
(1) the differential controller calculates the travel limit values of the left steering oil cylinder and the right steering oil cylinder;
when the actual steering angle is close to the maximum steering angle set by the strokes of the left steering oil cylinder and the right steering oil cylinder, stopping steering and recovering the previous constant speed state; in order to prevent the left steering oil cylinder and the right steering oil cylinder from being overloaded during differential steering, the extension and the shortening of the left steering oil cylinder and the right steering oil cylinder are limited during the differential steering, and the oil cylinders are limited and protected;
the relation between the elongation and the shortening of the left steering oil cylinder and the right steering oil cylinder and the actual steering angle beta is shown in a formula (3), and the maximum elongation and the shortening of the left steering oil cylinder and the right steering oil cylinder under the set maximum steering angle are calculated according to the formula (3);
in the formula:
a, the distance from a front vehicle connecting point A to a hinge point O, and a fixed value is designed for a hinge mechanism;
b, the distance from the rear vehicle connecting point B to the hinge point O, and a fixed value is designed for the hinge mechanism;
c, the distance from the rear vehicle connecting point C to the hinge point O is a fixed value designed for the hinge mechanism;
d is the distance from the front vehicle connecting point D to the hinge point O, and a fixed value is designed for the hinge mechanism;
α 1 angle of a to b, being hingedMechanism design fixed value;
α 2 the included angle between c and d is a fixed value designed for the hinge mechanism;
l 10 -the amount of shortening of the cylinder on one side,
l 20 -the amount of elongation of the cylinder on the other side,
β — actual steering angle;
(2) detecting an actual steering angle beta, and converting the actual steering angle beta into the elongation or shortening of the left steering oil cylinder and the right steering oil cylinder according to a formula (3);
(3) if the extension or the shortening of the left steering oil cylinder and the right steering oil cylinder reaches a stroke value, limiting protection is implemented, differential steering is stopped, and the steering angle is kept not to be increased any more.
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