CN102303655B - Wheel-legged combined-type robot platform - Google Patents

Abstract

The invention discloses a wheel-leg compound mobile robot platform. The robot platform includes a vehicle body, a front and a rear body, and a front and rear wheel-leg system. It is characterized in that the front wheel-leg system includes a steering system and a front swing leg system. Including steering motor, steering mechanism and steering wheel; front swing leg system includes front swing leg motor, front wheel leg bracket and front swing leg wheel, both subsystems are installed in the front box, and the front box uses The front short axle is connected with the body; the rear wheel leg system is composed of the car body, the rear swing leg system and the driving system, and both subsystems are installed on the rear car body; Connection; the body part mainly includes a corner motor, which is installed inside the body and has no relative movement with the body. The torque output end is connected to a gear, and the other gear meshed with it is rigidly connected to the rear short shaft. The motor realizes the left and right tilting of the vehicle body.

Description

A wheel-leg compound mobile robot platform

technical field

The invention relates to robot technology, in particular to an improved wheel-leg compound mobile robot platform.

Background technique

The advantage of the wheeled mobile robot platform is high speed and high efficiency, but the disadvantage is poor terrain adaptability. In order to adapt to the complex terrain environment, many robots now do not only use wheel-type mobile mechanisms, but more of them use compound mobile mechanisms such as wheel-track, wheel-leg or wheel-track-leg. The composite mobile robot platform adopts different travel strategies in different environments, which greatly improves the robot's forward speed and terrain adaptability, and has become a main direction for the development of outdoor robots today. The mobile robot platform is a basic platform on which control systems, detection systems and manipulators can be mounted, which can realize many functions that are difficult for ordinary robots to achieve. The robot platform is an independent module, which is independent from other platforms, which is convenient for secondary development and modification, and has a wide range of applications.

The essential problem to be solved by the robot mobile platform system is to design a set of optimal mechanical structure through comprehensive performance analysis of the robot’s working environment, specific functions to be realized and other technical indicators, so that the robot can achieve the specified actions and corresponding actions. control. The primary problem in the design of mobile platform system is to determine its travel mode, and the single travel mode mainly includes wheel type, leg type and crawler type. A single travel mode has its own characteristics and disadvantages. Since it cannot meet the requirements of complex terrain, most of them now use more than two composite travel modes. Such robot platforms have stronger adaptability to complex terrain. For example, the structural design and kinematic analysis of the composite mobile system of the new probe vehicle (Shang Weiyan et al., Mechanical Science and Technology, Vol. 28, No. 7, July 2009), the kinematics modeling and The analysis (Shang Weiyan et al., Journal of Aerodynamics, Vol. 24, No. 10, October 2009) uses a wheel-track compound mobile platform; also for example, the analysis and action planning of a leg-track compound robot autonomous obstacle surmounting (Wang Weidong et al., Harbin Institute of Technology Journal, Volume 41, No. 5, May 2009) uses a leg-shoe compound mobile platform; another example, a rolling wheel-legged mobile robot (Liu Fanghu, etc., Shanghai Jiaotong University Journal, Volume 32, No. 5 October 2001), the overturning stability analysis and control of wheel-legged robots (Tian Haibo et al., Acta Robotica Sinica, Vol. 31, No. 2, March 2009) use a wheel-leg composite mobile platform.

The existing wheel-legged robots mainly include the following types: 1. Six-wheeled mobile robots represented by the American Mars Rover Mars Exploration Rover. This type of robot can cross obstacles higher than its wheel diameter, but limited by its structure, the wheel Smaller, the distance between the body and the ground is too small, and it is necessary to frequently raise the legs to overcome obstacles in complex terrain environments, the driving efficiency is not high, and the energy consumption is large. 2. Represented by the triangular fork-type wheel-legged robot of Shanghai Jiaotong University, this type of machine has a strong ability to overcome obstacles and is easy to control, but it adopts the same travel method on flat terrain and complex terrain, which is inefficient and the chassis vibrates violently. Robotic platforms don't live long. 3. Represented by the wheel-leg variable structure mobile robot designed by Tsinghua University, this type of robot can realize the compound movement of wheels, legs, and wheel-legs. Although its ability to overcome obstacles is also strong, it requires eight motors and four million Directional wheels consume more power, and because of their smaller size, their load capacity and battery life are poor.

Contents of the invention

Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a wheel-leg compound mobile robot platform, which can meet various requirements of working in a complex field environment, and can climb slopes, cross ditches, Achieve smooth progress on uneven terrain, etc. On the premise of realizing the above functional requirements, the robot platform of the present invention has the characteristics of simple structure, easy control, low energy consumption and the like.

The technical solution of the present invention to solve the technical problem is to design a wheel-leg composite mobile robot platform, which includes a vehicle body, a front body and a rear body, a front wheel-leg system and a rear wheel-leg system, and is characterized in that :

The front wheel leg system includes two subsystems of a steering system and a front leg swing system, the steering system includes a steering motor, a steering mechanism and a steering wheel; the front leg leg system includes a front leg swing motor, a front wheel leg bracket and a front leg swing wheel, Both subsystems are installed on the front body; the front body is connected to the body by means of a front short shaft protruding from the rear of its front box; the steering mechanism is a planar four-bar mechanism installed at the lower part of the front box , protrude from the lower wall of the car body through the through hole in the lower part of the front box body, and the two ends of the connecting rod are respectively connected with the corner pins of the steering wheels on both sides through pins, so as to realize the same direction steering of the steering wheels, and the steering wheels are fixed on the front The front wheel leg bracket on the side wall of the box body is connected with the front box body; the front wheel leg bracket stretches out through the through holes on both sides of the front box body, and a front swing leg wheel is respectively installed at the left and right ends of the outside, and the front swing leg wheel can be Rotate within a certain range relative to the front box; the steering motor and the front swing leg motor are respectively installed in the appropriate position in the front box, and the movement is transmitted to the steering mechanism and the front wheel leg bracket through the gear connection to realize the steering and swing. leg;

The rear wheel leg system includes two subsystems of the rear swing leg system and the drive system; both subsystems are installed on the rear body; the rear body is connected to the body by a rear short shaft protruding from the front of the rear box; The drive system includes a driving motor, a differential, a pulley and a driving wheel. The differential is installed in the rear body, and the output shaft of the differential is stretched out from the through holes on both sides of the rear body. The drive wheels are respectively installed at the ends, and the gears are used to drive the driven wheels to move; the rear swing leg system includes a rear swing leg motor, a sleeve, a rear swing leg bracket and a rear swing leg wheel, and the sleeve is installed on one side of the output shaft of the differential. There is relative movement between the differential and the rear car body. The torque of the rear swing leg motor is transmitted to the rear swing leg bracket through the gear fixed on the sleeve to realize the swing leg within a certain angle range. The rear swing leg wheel is installed At both ends of the rear swing leg bracket, the power is transmitted to the rear swing leg wheel through the belt drive through the belt pulley fixed on the driving wheel and the rear swing leg wheel;

The body part mainly includes a corner motor; the corner motor is installed in the body, and there is no relative movement with the body; the torque output end of the corner motor is connected to a gear, and the other gear meshed with it is rigidly connected to the rear short shaft, The left and right tilting of the vehicle body is realized by the rotation of the angle motor.

Compared with the prior art, the robot platform of the present invention adopts a wheel-leg composite structure and only uses five driving motors, which has a simple structure and is easy to control. The wheeled method is used to travel on flat ground, and the energy consumption is greatly reduced; The wheel-leg compound method is adopted to advance, and the efficiency is greatly improved. Due to the special structural design, the invention can cross obstacles higher than the height of the chassis, cross a certain length of pits, and can adjust the roll angle of the robot, and has strong terrain adaptability.

Description of drawings

Fig. 1 is a schematic diagram of the overall three-dimensional structure of an embodiment of the wheel-leg compound mobile robot platform of the present invention.

Fig. 2 is a front structural schematic diagram of an embodiment of the wheel-leg compound mobile robot platform of the present invention.

Fig. 3 is a top view structural diagram of an embodiment of the wheel-leg compound mobile robot platform of the present invention.

Fig. 4 is a schematic structural diagram of the front wheel-leg system of an embodiment of the wheel-leg compound mobile robot platform of the present invention. in,

Fig. 4 (1) is the structural schematic diagram of front swing leg system;

Figure 4(2) is a schematic structural diagram of the steering system.

Fig. 5 is a schematic structural diagram of the rear wheel-leg system of an embodiment of the wheel-leg compound mobile robot platform of the present invention.

Fig. 6 is a schematic view of the body structure of an embodiment of the wheel-leg compound mobile robot platform of the present invention.

Detailed ways

Describe the present invention in detail below in conjunction with embodiment and accompanying drawing. The embodiment is based on the specific implementation carried out on the premise of the technical solution of the present invention, and provides detailed implementation methods and processes. However, the protection scope of the claims in the application of the present invention is not limited to the description scope of the embodiments.

The wheel-leg compound mobile robot platform (hereinafter referred to as robot or platform, see Fig. 1-6) designed by the present invention follows the concept of robot modular design and adopts modular design. The specific structural features are:

The platform of the present invention can be divided into three parts as a whole, namely the vehicle body 1 positioned at the middle part, the front vehicle body 2 positioned at the front portion of the vehicle body 1 and the rear vehicle body 3 positioned at the rear portion of the vehicle body 1; On the car body 2, the rear wheel leg system is installed on the rear car body 3; the front wheel leg system mainly includes two subsystems of the steering system and the front swing leg system; the rear wheel leg system mainly includes two subsystems of the rear swing leg system and the drive system ;The overall robot platform has four legs and eight wheels: front body 2 with two legs and four wheels, rear body 3 with two legs and four wheels and five motors: two for front body, 1 for body, and 3 for rear body .

The front wheel leg system of the robot of the present invention mainly includes a front swing leg system, a steering system and a front box 413 (see Fig. 4(1), 4(2)), and the steering system or module mainly adopts a planar four-bar structure , including steering motor 48, crank 414, connecting rod 47, steering short shaft 46, front axle 45, left and right symmetrical two supports 44,44', steering wheel 410 and transmission gear 49. The front box body 413 is a cuboid structure, its front is designed as a cylindrical surface for the sake of aesthetics, the side walls on both sides and the bottom are respectively processed with a through hole, and there is a protruding front short shaft 415 at the rear, which is used to realize the connection with the box body 413. Body 1 connection. The steering motor 48 is installed in the front casing 413, and the motion is transmitted to the crank 414 outside the front casing 413 through the transmission gear 49 and the through hole below the front casing 413. The crank 414 is connected with the connecting rod 47 by a pin, and the crank The swing of 414 within a certain angle is converted into the reciprocating movement of the connecting rod 47 relative to the front box body 413. The two ends of the connecting rod 47 are respectively connected with the pins of the short steering shaft 46, and the short steering shaft 46 is rigidly connected with the corresponding front axle 45. The swing of the short shaft 46 drives the front axle 45 to swing around its corresponding support 44, and the two ends of the front axle 45 are respectively equipped with steering wheels 410, thereby realizing the synchronous steering of the two steering wheels 410.

The front swing leg system includes a front swing leg motor 411, a front swing leg support 43, two left and right symmetrical front swing leg wheels 41, 41 ', a short shaft 42, 42 ' and a front transmission gear 412. The front swing leg motor 411 is installed in the front box body 413, and is connected with the front swing leg support 43 by the front transmission gear 412; the front swing leg support 43 stretches out the front box body 413 through the through holes on both sides of the front box body 413, Both ends of the front swing leg bracket 43 are respectively connected to the corresponding front swing leg wheel 41 through the short shaft 42 . In the initial state, the angle (initial angle) of the front swing leg bracket 43 relative to the horizontal plane is 60°. The length of the front swing leg support 43 and the radius of the front swing leg wheel 41 will determine the maximum obstacle-surmounting height of the robot and the width across the ditch. When needing to cross an obstacle, the front swing leg motor 411 drives the front swing leg support 43 to swing downward; when the front swing leg wheel 41 touches an obstacle, the steering wheel 410 and the front box body 413 are overhead; when the steering wheel 410 height reaches the obstacle During object height, front swing leg support 43 swings upwards, returns to initial state.

The rear wheel leg system (see FIG. 5 ) of the robot of the present invention includes a rear swing leg system, a drive system and a rear box 31 (see FIG. 3 ). The rear box 31 is a cuboid structure, corresponding to the front box 413. The back of the rear box 31 of the embodiment is designed as a cylindrical surface, and through holes are processed on both sides. Shaft 32 (see Figure 3).

The drive system or module 32 mainly adopts a gear-belt transmission composite structure (see FIG. 5 ), and mainly includes a drive motor 510, a differential 58, a pulley 52, a transmission belt 53, a rear axle 512, and two left-right symmetrical drive shafts. Wheels 54, 54' and drive gears 55, 55'. The driving motor 510 is installed in the rear casing 33, and the torque output of the driving motor 510 is output by the differential 58, and the output shaft of the differential 58 extends to the outside of the rear casing 33 through the through holes on both sides of the rear casing 33. The two ends of the differential 58 output shaft are respectively equipped with drive gears 55, and the torque is transmitted to the rear axle 512 through the drive gear 55, thereby driving the drive wheels 54 and the belt pulley 52 mounted on the rear axle 512 to move, so as to realize the movement of the overall robot. drive.

The rear swing leg system or module mainly includes a rear swing leg motor 57, a looper 511, a rear swing leg support 59, two left and right symmetrical rear swing leg wheels 51, 51' and a rear transmission gear 56. The looper 511 is installed on one side of the differential 58 and has relative movement relative to the differential shaft. The torque of the rear swing leg motor 57 is transmitted to the rear swing leg support through the rear transmission gear 56 installed at both ends of the looper 511 59, and then drive the rear swing leg support 59 to swing up and down to realize the leg swing function. The rear swing leg wheel 51 obtains power through the transmission belt 53 installed on the differential shaft, and itself also has driving capability, so that design can prevent the robot platform from losing power during the obstacle surmounting process. Back swing leg wheel 51 is in lifting state when not overcoming obstacles, and initial angle is 45 °.

The vehicle body 1 of the present invention is a cuboid structure (referring to Fig. 6), mainly comprises casing 61, corner motor 62 and a pair of meshing gear 63,63 '. The control system of the robot is mainly installed inside the vehicle body 1, and the internal structure of the vehicle body 1 is required to be as simple as possible. The embodiment only has a corner motor 62 and a pair of meshing gears 63. In order to prevent the body 1 from contacting the ground during the tilting process, the lower part of the cuboid body 1 of the embodiment is designed as a relatively large arc transition. The front and rear of the box body 61 are respectively processed with a through hole, which is used to realize the connection with the front and rear car bodies 2, 3, wherein the connection with the front car body 2 is only simple. Angle motor 62 is installed inside the vehicle body 1, the position is behind, and there is no relative movement between the body 1, the angle motor 62 is connected with the active meshing gear 63; 32 rigid connections, when the corner motor 62 rotates, the vehicle body 61 will form the rear short shaft 32 that the rear vehicle body 3 stretches out to swing left and right as an axis, so as to achieve the purpose of tilting.

When the robot platform travels on uneven ground, in order to avoid frequent swinging of legs to overcome obstacles, the diameters of the steering wheel and the driving wheel of the preliminary design of the embodiment of the present invention are 200mm, and the support lengths of the front and rear swing leg supports are 240mm (for Easy installation and mass production, all wheels have the same diameter). The platform length (i.e. the distance between the steering wheel axle and the driving wheel axle) is 600mm, and the width (i.e. the distance between the two steering wheels) is 540mm. The distance between the bottom of the vehicle body 1 and the ground is the radius of the wheel. When the car crosses an obstacle less than 100mm, that is, less than 1/2 of the diameter of the wheel, the wheel can directly pass over the obstacle without swinging the legs. When the car body needs to cross the trench, when the width of the trench is smaller than the radius of the wheel, the robot platform can pass directly. When the width of the trench is greater than the radius of the wheel, the two front and rear swing leg motors are controlled by commands to rotate, and they rotate 60° according to the initial angle. And 45°, so that the front and rear swing leg wheels are in contact with the ground, calculated according to the length of the swing leg bracket, the platform can pass through a maximum width of 400mm (240+100+100=440mm, 240mm is the length of the swing leg bracket, 100mm is the wheel radius , take 400mm) trench.

The four wheels at the front of the robot platform of the present invention are all driven wheels, and the four wheels at the rear drive the robot to advance. The drive system itself is state-of-the-art, modeled on the differentials used on cars.

When the robot platform advances on a rough road, if the car body tilts left and right, the robot platform can keep the car body balanced by adjusting the corner motor 62 to avoid overturning. The robot can be installed with an inclination sensor to give feedback to the control system to achieve real-time adjustment. In addition, compared to wheel-leg composite robots with other structures, the robot platform of the present invention can realize stable contact between the steering wheel and the driving wheel and the ground (no wheel suspension phenomenon) no matter what road surface the robot platform is traveling on, which improves the robot platform in the process of movement. in the stability. The robot platform designed by the invention has strong ability to cross obstacles. When the robot encounters an obstacle that cannot be directly crossed, it can cross a vertical obstacle up to 1.2 times the diameter of the wheel through the cooperation of the front and rear wheel leg systems. According to the obstacle-surmounting principle of the robot, the highest obstacle height that the embodiment robot platform can cross is 240-100+100 (240 is the rear leg length, 100 is the wheel radius), taking 200mm, that is, when the ranging sensor on the car body detects When the height of the obstacle is greater than 200mm, the robot platform adopts the steering strategy; when the height of the obstacle is lower than 200mm, the obstacle surmounting strategy is adopted. The total weight of the robot in the embodiment is 70kg, and the safety factor is designed to be 1.6. When the robot platform crosses obstacles, the maximum power consumed by the five motors is 100W, the maximum torque is 1500N·m, and the load can reach 20kg. Up to 8 hours, excellent performance, a wide range of applications.

In the previously designed seven-wheel and seven-leg compound mobile robot, the six wheels except the obstacle-crossing wheel are in contact with the ground in the initial state, so when the robot moves from the horizontal plane to the slope or turns on the slope, the six wheels cannot At the same time, it is in contact with the ground, making its stability and passability worse. The robot platform of the present invention has four legs and eight wheels. In the same above-mentioned road conditions, the steering wheel and the driving wheel can be in full contact with the ground, thereby improving its stability; in addition, it is simpler in structure and consumes less power than the existing robot. Low.

It should be added that the location words such as "front, back; left, right; up, down" in the present invention are for clarity of description and only have relative meanings. In general, the forward direction of the robot is used as the reference for other orientation words.

What is not mentioned in the present invention is applicable to the prior art.

Claims (2)

1. The utility model provides a wheel leg combined type mobile robot platform, this robot platform includes automobile body, preceding automobile body and back automobile body, preceding wheel leg system and rear wheel leg system, its characterized in that:

the front wheel leg system comprises a steering system and a front swing leg system, wherein the steering system comprises a steering motor, a steering mechanism and steering wheels; the front swing leg system comprises a front swing leg motor, a front swing leg bracket and a front swing leg wheel, and the two subsystems are arranged on the front vehicle body; the front car body is connected with the car body by a front short shaft extending out of the rear part of the front box body; the steering mechanism is a plane four-bar mechanism, is arranged at the lower part of the front box body, extends out of the lower wall of the vehicle body through a through hole at the lower part of the front box body, two ends of a connecting rod are respectively connected with corner pin shafts of steering wheels at two sides through pins to realize the same-direction steering of the steering wheels, and the steering wheels are connected with the front box body through front wheel leg supports fixed on the side wall of the front box body; the front wheel leg support extends out through holes on two sides of the front box body, a front swing leg wheel is respectively arranged at the left end and the right end of the outer part of the front wheel leg support, and the front swing leg wheel can rotate in a certain range relative to the front box body; the steering motor and the front swing leg motor are respectively arranged at proper positions in the front box body, and the motion is transmitted to the steering mechanism and the front swing leg bracket through gear connection, so that steering and leg swinging are realized;

the rear wheel leg system comprises a rear swing leg system and a driving system; the two subsystems are both arranged on the rear vehicle body; the rear car body is connected with the car body by a rear short shaft extending from the front part of the rear box body; the driving system comprises a driving motor, a differential mechanism, belt wheels and driving wheels, the differential mechanism is arranged in the rear vehicle body, an output shaft of the differential mechanism extends out of through holes on two sides of the rear vehicle body, the two extending shaft ends are respectively provided with the driving wheels, and the driving wheels are driven by gears to move; the rear swing leg system comprises a rear swing leg motor, a sleeve, a rear swing leg support and a rear swing leg wheel, wherein the sleeve is arranged on one side of an output shaft of the differential mechanism and moves relative to the differential mechanism and the rear vehicle body;

the vehicle body part mainly comprises a corner motor; the corner motor is arranged in the vehicle body and does not move relative to the vehicle body; the torque output end of the corner motor is connected with one gear, the other gear meshed with the torque output end of the corner motor is rigidly connected with the rear short shaft, and the left and right inclination adjustment of the vehicle body is realized by the rotation of the corner motor.

2. The wheel-leg combined type mobile robot platform as claimed in claim 1, wherein the diameters of the steering wheels and the driving wheels are both 200mm, the distance between the wheel axle of the steering wheels and the wheel axle of the driving wheels is 600mm, the distance between the two steering wheels is 540mm, the length of the support of the front and rear swing leg supports is both 240mm, and the distance from the bottom of the vehicle body to the ground is the radius of the wheels.

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