AU2019101190A4

AU2019101190A4 - Wheel-legged integrated hexapod robot

Info

Publication number: AU2019101190A4
Application number: AU2019101190A
Authority: AU
Inventors: Zhewen Chen; Songxu Han; Xiaojian LI; Caoyu Xie; Kaicheng Yu; Hongyi ZHU
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-02
Filing date: 2019-10-02
Publication date: 2020-01-30
Anticipated expiration: 2027-10-02

Abstract

This invention is designed mainly for routine inspection, rescue missions in multi-terrains environment. The main process of developing this hexapod based wheel-legged robot includes mechanism structure design, electronic devices configuration, gaits' control adjustment and pathing route simulation. With the use of transformable wheel-legs, the robot can run flexibly in flat under the wheeled mode, and through the gear and mechanism system, it would shift to legged mode to show enough capability for overring the unstructured obstacles. As the expectation, this robot would have bright prospects for variable terrains application and substitute current rivals by its higher efficiency and adaptability. Fig.5 Fig.6

Description

TITLE

Wheel-legged integrated hexapod robot

FIELD OF THE INVENTION

The invention as one of the latest research subfields of legged locomotion robot, by using the transformable wheel-leg structure to obtain high efficiency and adaptability in multi-terrains for routine inspection, rescue missions or other related work.

BACKGROUND OF THE INVENTION

Robots with locomotion of multi-legged, wheeled and many other kinds are widely used to substitute people in some special work. They are expected to face with adverse environments that cannot directly enter by human because of the space limitation or potential threat to life security, to detect variable sensate information in high efficiency, for supporting further strategic decisions making. As these properties, there are bright prospects for their application, especially including the rescue missions and certain core areas safeguard situations. For chasing the potential benefits, amount of research teams and companies are dropping in this field’s study, which objectively bring giant improvements on the robot relative technologies. Following the times, most universities currently have their own labs focus on this direction, and the related company,

2019101190 02 Oct 2019

Boston Dynamic, is looked to further increase by public because of their high-performance bionic robots.

The locomotion type normally is single in most robots, which is a significant drawback for complex terrains application. Generally, wheeled robot can be disposed quickly in flat, and traditional legged robot is easy to handle unstructured environments, but both two lose the advantages that their counterparts have. To solve this problem, some high-tech companies, like Boston Dynamic, tend to design the leg and adjust the control system of robot to simulate skeletal structure and the complicate gaits of higher animals to approach some advanced achievements. There is no doubt that it is a brilliant solution, however, for this kind of design would always have large body which cannot be operated in tight space, besides, the complex system increases the difficulty of maintenance and the overall cost.

Wheel-legged robot, combined the advantages of both wheeled and legged, may provide a new solution to overcome those mentioned problems. As one of latest research subfields of conventional legged locomotion type, it seems like a way to obtain a perfect balance between small body and multi-terrains adaptability. The core design part is the transformable wheel-leg structure; robot with the locomotion by wheel-leg which could transfer the configurations of its ‘feet’ to fit special cases, which can combine wheeled and legged robots’ advantages

2019101190 02 Oct 2019 but avoid their shortcomings.

By using this wheel-legged plan, it would dramatically decreases the difficult of overall design, but only focus on the wheel-leg combination, besides, its advantages and the no need of huge body, which could easily to cross through unstructured terrains without lose flexibility in limited space. Apart from these, this design should also have a relative low price and maintenance cost.

SUMMARY

According to the advantages in theories, this wheel-legged robot is capable to substitute those current used rivals in typical application conditions, where restrain human by space limitation and threat to life safe. So that, it is available to detect variable sensate information at much higher efficiency than single-function wheeled or hexapod robots, in rescue missions of wasteland, core areas safeguard or military intelligence collections. Normally, this wheel-legged robot uses the wheel mode for flexible disposition in surface, thence the wheel transfer to leg mode, if necessary, for overring other unstructured terrains; by absorbing the positive properties from counterparts, wheel-legged robot can be much more compatible.

The core parts of this invention are based on bionics, which is the original design inspiration of this wheel-legged robot. From the early years’

2019101190 02 Oct 2019 research on multi-legged robot, the great interests were noticed in the study of living beings’ motions, the frameworks of skeletal activity and the relative control mechanisms. Following the similar methodology of the predecessors’ work and carrying on some new considerations of the expected applications, this wheel-legged robot invention has copied the merits from lizard and some multi-legged inserts. Lizard, especially those kinds live in jungles, has ability to run through the thicket at a lightning velocity, and this gift is profit from its special foot structure and gait; the front and rear two pairs of legs would roughly rotate along the joint axials by turns, to over the complex terrains. However, it is hard to achieve such a high speed like lizard to obtain the stability by the inertia, so that, the robot is added more legs from four to six, which is learning from the multi-legged inserts like spider to keep the overall system stable.

With this mentioned blueprint, these mechanical contents of wheel-leg have been well-designed to meet the requirements of moving and the configurations transformation. The wheel is divided to two semicircle part which mate to the center transform gear through the rock and pinions; while the center gear is driven by the small motor on the boss of the wheel, the two semicircle would be possible to shift the shapes just in one degree of freedom between wheel and leg. Besides, the deformation system cage at the center not only can hold these gears’ system but provide a solid fixed in both wheel and leg gestures. For the whole body

2019101190 02 Oct 2019 moving, all six wheel-legs are directly linked with their own motors, and to consider the angle’s settings and the step rotation requires, both main motors and tiny transforming motors are chosen as high performance step motor.

Apart from the fixed locomotion issues, this robot has variable equipment and sensors to support the operations and detect widely senate information in special situations. The route pre-set by the computer, with the inner GPS navigation and interference from manipulator’s control, robot can achieve certain level of semi-automatic. The infrared instrument and sonar devices around the body would provide real time data to adjust the robot gestures, gaits, speed, direction for overring or passing round the obstacles, and the panoramic camera on the above face will provide visual signal to observe the surrounding conditions. For any other equipment, there are several operation platforms to connect any possible detected sensors to improve the adaptability or even can set a tiny lab to collect and analysis nearby air sample for meeting the rescue and other demands.

Equipped with several of essential attachments, driven by six main motors and six small transforming motors, the power supply should be strong enough to undertake this large load. For this robot, the lithium cell would be selected, and because of the plenty room inside the body, the size adjustment should be available based on the practical test.

2019101190 02 Oct 2019

In conclusion, this wheel-legged invention is a production based on a hexapod robot to compromise the speed, the obstacle crossing function and the system steady as pervious analyses. Through the computer and manipulator’s control, it could meet the design purposes to handle dangerous, tactical jobs by calling variable sensors and equipment.

DESCRIPTION OF THE DRAWINGS

The appended drawings are only for the purpose of description and explanation but not for limitation, wherein:

Fig.l: Overall views of the wheel-legged robot

Fig.2: Overall views of the wheel-leg details

Fig.3: Transformation of wheeled and legged modes

Fig.4: Main body views and core inner structures

Fig.5: Wheeled mode view with advance attachments assembled

Fig.6: Overall views of legged mode in tripod gait

Fig.7: Overall views of legged mode in tripod gait

Fig.8: Overall views of legged mode in tripod gait

Fig.9: Fegged mode view in waving gait

Fig. 10: Overring the footstep in waving gait

Fig 11: Detect the obstacle and turn around in tripod gait

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Fig. 12: System structure diagram

Fig. 13: The flowchart of robot program logic in complex terrains.

DESCRIPTION OF PREFERRED EMBODIMENT

In order that the wheel-legged robot invention can be more readable, the main parts of this structure are listed as reference, accompanying with the operation simulation drawing to illustrate the embodiments of this present invention.

Referring to Figs. 1,2,3,4

1. Semicircle part of the wheel	2. Rock and pinions
3. Deformation cage	4. Countersunk head screw
5. Auxiliary stepper motor	6. Input transmission gear
7. Boss of the wheel	8. Friction surface of the tyre
9. Body of the robot	10. Mother board
11. Power supply	12. Main stepper motor
13. GPS module	14. Wide angle camera

15. Multifunction platform

The overall relationship of the main components is shown in figure 11. It is divided in two parts: sensory system and driving system. Sensory system mainly consists of navigation system and camera system, and users can append other sensors according to their need. Navigation system includes a GPS module, an Ultrasonic module and an infrared

2019101190 02 Oct 2019 instrument. Driving system includes deformation system, foot and engine. Engine includes six main step motors and six auxiliary step motors.

The Sensory system is located inside of robot’s body. The GPS module is placed at the back of the body, and an aerial that is connected to it extends outside. It mainly serves to inform users the overall location of the robots and to achieve the target quickly. The Ultrasonic modules and the Infrared instruments are on the front and behind the body. Each side have two of them. The Ultrasonic modules can detect whether there is an obstacle in front, while the Infrared instruments can measure the height of the obstacle. After the mother board receives and process these signals, the robot will have feedback order to go through the obstacle or make a detour. Based on these two modules, users can also know detailed information of the environment. The camera system is placed on the center of the top. There is semi-sphere glass cover the camera, so it would be protected well in field. The users can operate remote controls to turn the cameras, which gives them a wider vision.

The driving system is on the two sides of the robot. Each side has three driving units, and each unit consists of two feet, a main step motor, an auxiliary step motor and the deformation gear mechanism system. The function of the main step motors drives the axle to march, no matter in

2019101190 02 Oct 2019 the wheel mode or leg mode. The wheel is divided to two semicircle part which mate to the center transform gear through the rock and pinions; while the center gear is driven by the small auxiliary motor on the boss of the wheel, the two semicircle could be possible to shift the shapes just in one degree of freedom between wheel and leg. Besides, the deformation system cage at the center not only can hold these gears’ system but provide a solid fixed in both wheeled and legged gestures. When in the leg mode, two feet are fully deployed with the relative size increase to the designated spot, so that, it is easier for robot to over complex terrain.

Example. 1

The robot is placed in a test field in wheeled mode. First, turn on the power and the robot control system. The control system would scan the surrounding environment through the sensor at once, then, the stepper motor starts to work by the order based on this collected information. On a flat surface, the robot's forward gestures will be adjusted by the control system to complete the straightforward task. For those unstructured terrains (not an obstacle), once being detected, the control system will issue a foot deformation command to start the auxiliary stepper motor associated with the deformation and decelerate the main stepper motor at the same time. After the wheel-leg structured has been transformed completely, the auxiliary stepper motors will be stalled and speed up the

2019101190 02 Oct 2019 main motor to march. Finally, the robot successfully converts the mode from wheeled to legged. (NOTE: the default gesture now is tripod gait).

Example.2

Test of the robot's ability to over obstacles. Based on the ultimate obstacle height which has already been obtained in software simulation, the following judgment system and operation control are designed.

1. Once the sensor detects the front obstacle is lower than the ultimate obstacle height in theory (90% of the ultimate obstacle height in computer simulation), a serious of control signal will issue the obstacle-obeying command. In general, tripod gait will shift to the waving gait and decelerate the forward speed which increase the pulling force. While the obstacle crossing operation is completed, and no more obstacle can be determined by sensors, another gesture transition feedback will command the robot return to the tripod gait with the velocity recovery.

2. If the front obstacle height is detected as unachievable by comparing the ultimate obstacle height in theory, a turning round command will be issued. The robot will perform a direction steering action immediately, change the head direction with certain degrees interval for times, until an available route is found by the sensor system. At the same time, the main motors speed would slow down to support the whole control procedure.

Claims

1. Wheel-legged integrated hexapod robot, wherein this wheel-legged integrated hexapod robot operated by self-contained programmable semi-automatic control with certain manipulator’s radio remote support can perform in various tasks, such as patrol, routine inspection and rescue missions, mounting the GPS navigation system, sonar and infrared instruments, this robot, which is capable for real time environment analysis and command processing, the wheel-legged transformation structure makes the robot obtain a perfect balance between small body and ability to over obstacles, and comparing with current hexapod, wheeled robots, this invention has the advantages in both quick disposition and multi-terrains adaptability, which are rarely achieved by rival productions; So that, showing a bright application and marketing prospects.