TWI401070B - Stewart platform seat mechanism and controlling method thereof for intelligent robotic wheelchair - Google Patents

Description

Stewart platform seat mechanism of intelligent robot wheelchair and control method thereof

The present invention relates to a seat mechanism for a wheelchair, and more particularly to a seat mechanism designed for a Steward Platform seat mechanism of a smart robotic wheelchair.

For people with limited mobility, such as the disabled, the elderly, etc., the use of wheelchairs can assist in their actions. However, for some users with insufficient upper limb strength or elderly people, the use of electric wheelchairs is a possible option because they cannot promote their own wheelchairs. . However, the difficulty of controlling the electric wheelchair is still quite high, and for most users, it is still difficult to use. In order to improve the operation difficulties of these wheelchairs, in recent years, the research direction of wheelchairs has begun to shift the wheelchair from completely passive and user-controlled, so that the wheelchair itself has the ability to sense and judge similar robots.

In 1995, Miller and Slack, two engineers at MITRE in the United States, proposed the term "robotic wheelchair" in their research literature. Their papers describe the prototypes of two robotic wheelchairs, which are used in robots. The measurement and navigation technology, applied to wheelchair operations, can help operators avoid obstacles, reach predetermined locations, and pass through crowded environments [Miller and Slack, 1995], creating the research field of "robotic wheelchairs".

However, most of the current research directions of manufacturers focus on the development of hardware structures, such as seat cushions, awnings, rims, and brake structures. The part that develops the seat mechanism is for the user to make posture changes. The most part is the backrest, the footrest adjustment and the seat cushion adjustment. The electric pad adjustment is mainly the adjustment of the upper and lower heights, and there is no left and right traverse function.

The invention provides a smart robot wheelchair Schroder platform seat mechanism design, the Stewart platform mechanism is applied to a wheelchair, and a four-axis Stewart platform seat mechanism is designed, which is lightweight and high. The effect of rigidity and multi-degree of freedom adjustment.

The invention provides a smart robot wheelchair of the Stewart platform seat mechanism, which comprises a movable plate, a fixed frame and four variable length connecting rods. The fixing frame has a first contact, a second contact, a third contact and a fourth contact, wherein the first contact and the second contact are located above the movable plate, and the third contact and the fourth The contacts are located below the movable plate. The first end of the first variable length link is pivotally connected to the first contact, and the second end of the first variable length link is pivotally connected to the movable plate. The first end of the second variable length link is pivotally connected to the second contact, and the second end of the second variable length link is pivotally connected to the movable plate. The first end of the third variable length link is pivotally connected to the movable plate, and the second end thereof is pivotally connected to the third contact. The first end of the fourth variable length link is pivotally connected to the movable plate, and the second end thereof is pivotally connected to the fourth contact. The fixing frame has a base and a side stand, the first contact and the second contact are located on the side stand, and the third contact and the fourth contact are located on the base. Wherein, the position of the movable plate changes with the length of the first to fourth variable length links.

In an embodiment of the invention, one end of the variable length link is connected to the movable plate via a ball joint, and is connected to the fixed frame via a universal joint. Conversely, the variable length link can also be connected to the movable plate via a universal joint and to the fixed frame via a ball joint. In addition, both ends of the variable length link may be pivotally connected to the movable plate and the fixed plate by using the same universal joint or ball joint. The fixing frame has a first limiting member and a second limiting member respectively disposed under the first contact and the second contact, the first limiting member having a first bearing inclined surface to limit the first variable length connecting rod The angle of inclination of the second limiting member has a second bearing slope to limit the angle of inclination of the second variable length link. The seat mechanism further includes a Mecanum Wheel set disposed below the mount.

In summary, the seat mechanism of the wheelchair provided by the present invention has a four-axis drive mechanism, and four variable length links are used to adjust the position and height of the seat cushion, so that the seat cushion can have left and right traverse, and move back and forth. Adjustment functions such as flipping make the user more convenient. The seat mechanism of the wheelchair of the present invention has the advantages of high rigidity, multiple degrees of freedom, and weight reduction.

The above described features and advantages of the present invention will be more apparent from the following description.

In the following, the invention will be described in detail by the embodiments of the invention, and the same reference numerals are used in the drawings.

1 is a schematic view of a Stadford platform seat mechanism of a smart robotic wheelchair according to an embodiment of the present invention. The seat mechanism 100 includes a fixed frame 110, a movable plate 120, and four linear brakes 141 to 144. The fixing frame 110 includes a base 112 and two side stands 114. The side stand 114 has two contacts 11a, 11b above the movable plate 120. The base 112 has two contacts 11c and 11d below the movable plate 120. . The movable plate 120 has corresponding four contacts 12a, 12b, 12c, 12d, wherein the contacts 12a, 12b are located on the first side of the movable plate 120, and the contacts 12a, 12b are located on the movable plate 120 relative to the first The second side of the side. One end of the linear brake 141 is pivotally connected to the contact 11a on the fixed frame 110, and the other end is pivotally connected to the contact 12a on the movable plate 120; one end of the linear brake 142 is pivotally connected to the contact 11b on the fixed frame 110, and One end of the linear brake 143 is pivotally connected to the joint 11c on the base 112, and the other end is pivotally connected to the joint 12c of the movable plate 120; one end of the linear brake 144 The other end is pivotally connected to the contact point 12d on the movable plate 120. In the present embodiment, the linear brakes 141-144 are used to implement variable length links, and the position of the movable plate 120 can be determined by the length of the linear brakes 141-144. It is worth noting that variable length links can be implemented in other ways and are not limited to the use of linear brakes 141-144.

Each of the linear brakes 141 to 144 has the same structure, and both ends of each of the linear brakes 141 to 144 are respectively provided with a ball joint and a universal joint to be pivotally connected to the movable plate 120 and the fixed frame 110. Taking the linear brake 141 as an example, the linear brake 141 has a body 141a and an axial rod 141b, and one end of the axial rod 141b is located in the body 141a and is coupled to the body 141a. The axial rod 141b of the linear brake 141 is axially displaceable to adjust the length of the axial rod 141b. The front end of the axial rod 141b is provided with a ball joint 151 to be pivotally connected to the joint 12a on the movable plate 120. The bottom of the body 141a has a universal joint 161 to be pivotally connected to the joint 11a on the lateral frame 114.

Similarly, the front end of the axial rod of the linear brake 142 has a ball joint 152 for pivoting to the joint 12b of the movable plate 120, and the bottom of the body has a universal joint 162 for pivoting the joint on the lateral frame 114. 11b. The front end of the axial rod of the linear brake 143 has a ball joint 153 for pivoting to the joint 12c of the movable plate 120, and the bottom of the body has a universal joint 163 for pivoting to the joint 11c on the base 112. The front end of the axial rod of the linear brake 144 has a ball joint 154 for pivoting to the joint 12d on the movable plate 120, and the bottom of the body has a universal joint 164 for pivoting to the joint 11d on the base 112.

As shown in FIG. 1, the four linear brakes 141 to 144 are connected to the movable plate 120 to form a four-axis drive mechanism. Wherein the linear brakes 141, 142 are connected to the movable plate 120 from above the movable plate 120 to provide a suspended pulling force to the movable plate 120, and the linear brakes 143, 144 are connected to the movable plate 120 from below the movable plate 120 to provide an upward supporting force to the movable plate 120 Board 120. The linear brakes 141 to 144 can withstand axial forces (pull or pressure). The position of the movable plate 120 changes with the length of the linear brakes 141 to 144. The calculation between the length of the linear brakes 141 to 144 and the position of the movable plate 120 can be calculated by Forward kinematics or Inverse kinematics.

Before importing kinematics, first create two space vectors as follows:

(1) Cartesian space[ x , y , z , α, β, γ] ^T , where [ x , y , z ] represents the position of the origin of the movable plate, [α, β, γ] is the movable plate and x , y , the angle between the three axes of z .

(2) Joint space [ S ₁ , S ₂ , S ₃ , S ₄ ] ^T , where S _i represents the length of the four linear brakes, respectively.

When the operation from Joint space to Cartesian space belongs to forward kinematics, it is called reverse kinematics. However, even if the lengths of the four linear actuators are determined first, the universal joints 151 to 154 connected to the linear brakes 141 to 144 may have different directions, resulting in a position and an angle of the movable plate 120. First, the operation of the forward kinematics will produce a majority solution. Reverse kinematics does not have such a problem. First, given the coordinates and angle of the movable plate 120, the length of the four linear actuators 141-144 obtained by operation is the only solution. Therefore, in practical application, the positioning method of the movable plate 120 in this embodiment is preferably a reverse kinematic manner.

In this embodiment, the movable plate 120 can be used to set the seat cushion, and then perform functions such as vertical height adjustment, left and right lateral adjustment, and front and rear reverse adjustment. When the linear actuators 143, 144 are shortened in length and the linear actuators 141, 142 are elongated in length, the vertical height of the seat cushion can be lowered. Conversely, when the linear actuators 141, 142 are shortened in length and the linear actuators 143, 144 are elongated in length, the vertical height of the seat cushion can be raised. When the linear actuators 141, 143 are shortened in length, the linear actuators 142, 144 are elongated in length to achieve the effect that the vertical height of the seat cushion is constant and traversing to the right. Conversely, when the linear actuators 141, 143 are shortened in length, the linear actuators 142, 144 are elongated in length to achieve the effect that the vertical height of the seat cushion is constant and traversing to the left. As can be seen from the above, as long as the linear actuators (141, 143 or 142, 144) on the same side increase in length or decrease in length, the movable plate 120 is traversed to the other side. When the linear actuators 143, 144 are elongated in length, the linear actuators 141, 142 are also elongated in length to achieve the effect of the seat cushion rolling backward. Conversely, when the linear actuators 143, 144 are shortened in length, the linear actuators 141, 142 are also shortened in length to achieve the effect of the seat pad rolling forward. As long as the linear actuators (141, 142 or 143, 144) above or below are simultaneously increased in length or reduced in length, the movable plate 120 is tilted forward or backward.

As can be seen from the above, as long as the lengths of the linear actuators 141 to 144 are changed, the movable plate 120 can be adjusted in height, inclination, and lateral traverse, and the positional relationship between the different length combinations and the movable plate 120 can be utilized. The kinematics or inverse kinematics are inferred, and it should be easily inferred by those skilled in the art after the description of the above embodiments, which will not be described here.

The side stand 141 is provided with two limiting members 116, 118 respectively disposed under the contacts 11a, 11b. The stop members 116, 118 have bearing abutments facing the linear brakes for defining the angle of inclination of the linear actuators 141, 142 and the direction of movement thereof. For example, FIG. 2 is a schematic diagram of the limiting member 116 according to the embodiment. The limiting member 116 has a bearing surface 116a. The linear brake 141 will bear against the bevel 116a to form an angle of inclination of, for example, 45 degrees. When the linear brake 141 is displaced to the left and right, it is limited to the bearing bevel 116a and moves along the bearing bevel 116a. Similarly, the linear brake 142 will bear against the bearing slope of the limiting member 118 and form an angle of inclination of, for example, 45 degrees. In a state where the movable plate 120 is horizontal, the linear brakes 141, 142 also form an angle of, for example, 45 degrees with the movable plate 120. Since the limiting members 116, 118 limit the inclination angle of the linear brakes 141, 142 and the direction of their movement, the stability of the seat cushion can be increased, and the swaying when the position is adjusted can be avoided to cause discomfort to the user.

Referring to FIG. 1 , in the embodiment, the seat mechanism 100 further includes wheels 171 174 174 disposed on the bottom side of the base 112 , and the wheels 171 174 174 can be driven by a driving motor and a control device (not shown). To move the entire seat mechanism 100. Among them, the wheels 171~174 can be replaced by the McLaren wheelset formed by four Mecanum Wheels. Please refer to FIG. 3A and FIG. 3B , which are schematic structural diagrams of the McLaren wheel. The outer ring of the wheel of the McLaren wheel 300 has a free roller 311 at 45 degrees to the axis. When the wheel rolls, the ground gives a frictional force of 45 degrees to the wheel. The friction can be divided into X component and Y component. By changing the direction of the XY component force by the positive or negative rotation or stop of the wheel, the platform can be moved in various ways. The way to set up the four McLaren wheels is shown in Figure 4. Figure 4 shows the layout of the McLaren wheel set. The seat mechanism 400 is schematically illustrated, and a McLaren wheel set consisting of four McLaren wheels 410-440 is disposed below. Among them, the front two McLaren wheels 410, 420 are a group, and the rear two McLaren wheels 430, 440 are a group. The direction in which the free rollers 411, 421, 431, 441 are disposed is symmetrical. The seat mechanism 400 can have an omnidirectional movement function of translation and rotation by the direction of rotation of the McLaren wheels 410-440.

Further, it is to be noted that the linear brakes 141 to 144 are disposed above and below the movable plate 120 in such a manner that the two shafts are on the upper side and the two axes are on the lower side. The distance between the contact 11a and the contact 11b is greater than the distance between the contact 12a and the contact 12b. The distance between the contact 11c and the contact 11d is greater than the distance between the contact 12c and the contact 12d. Therefore, the linear brakes 141, 142 are connected to the movable plate 120 from the outer side in the inward direction and from the upper side, and the linear brakes 143, 144 are connected to the movable plate 120 from the outer side in the inward direction and from the lower side. It should be noted that the inclination angle between the linear brakes 141 to 144 may be determined according to design requirements, and the present invention is not limited. The holder 110 assumes an L shape, but the appearance of the holder 110 of the present invention is not limited. The linear brakes 141 to 144 are linear brakes of the model LAS3-1-1-150-24G produced by Daikin Microsystems Co., Ltd., but the present invention does not limit the type of linear brakes. Position sensing elements, such as photo interrupter position feedback means, may be provided in the linear brakes 141-144 for position feedback. The linear brakes 141-144 may be motor brakes (e.g., TOSHIBA, model TA7257P) linear brakes 141-144, and the current length is determined by its feedback device to determine the adjusted speed and elongation distance.

In addition, when adjusting the seat cushion height and position of the seat mechanism 120, in order to make the user more comfortable and safe, the seat cushion movement process needs to be smooth and stable. The calculation between the length of the variable length links 141-144 and the position of the seat mechanism 120 can be calculated by Forward kinematics or Inverse kinematics.

Before importing kinematics, first create two space vectors as follows:

(1) Cartesian space[ x , y , z , α, β, γ] ^T , where [ x , y , z ] represents the position of the origin of the movable plate, [α, β, γ] is the movable plate and x , y , the angle between the three axes of z .

(2) Joint space [ S ₁ , S ₂ , S ₃ , S ₄ ] ^T , where S _i represents the length of the four linear brakes, respectively.

When the operation from Joint space to Cartesian space belongs to forward kinematics, it is called reverse kinematics. However, even if the lengths of the four variable length links 141 to 144 are determined first, the universal joints of the seat mechanism 120 and the variable length links 141 to 144 may have different directions, resulting in the seat mechanism. The position and angle of 120 are different, so the majority of the solution is generated by the forward kinematics calculation. There is no such problem in reverse kinematics. Given the coordinates and angle of the seat mechanism 120, the length of the four variable length links 141-144 obtained by operation is the only solution.

It is only during the adjustment process that the length of the variable length links 141-144 requires considerable system computing resources. Therefore, in terms of driving, the present invention cooperates with a method of calculating a variable length link length. The seat cushion can be disposed on the movable plate 120. The present invention establishes a feasible working space of the center point of the seat cushion (the center point of the movable plate 120), and uses the center point of the seat cushion as a reference coordinate to record the moving range of the seat cushion and digitize the working space. Chemical. The information of this workspace will store the coordinates of the coordinates of the center point of the seat cushion and its corresponding variable length links 141-144. That is, the workspace will include a plurality of reference coordinates and corresponding four variable length link length values to correspond to the length of the variable length links 141-144.

The variable length link length corresponding to each reference coordinate takes into account the level of the movable plate 120 to avoid the occurrence of tilting and flipping. Since the reference coordinates are used to indicate the center position of the movable panel 120, two adjacent reference coordinates can be used to indicate two adjacent position points that the movable panel 120 can reach in space.

When the user needs to adjust the position of the seat cushion, the seat mechanism 100 pre-plans each movement path of the seat cushion according to the working space to avoid an unexpected posture, for example, the seat cushion is inclined to cause inconvenience to the user. The moving path is composed of a plurality of adjacent reference coordinates in the workspace, and can be connected to the target position point set by the user from the current position point.

Therefore, when the user needs to traverse the seat cushion left and right, during the movement, the movable plate 120 will remain horizontal without causing the user to feel uncomfortable or risk of falling, so in addition to the control, in addition to making 4 pieces variable The length links 141~144 (linear actuators) are synchronized, and the seat cushion must be moved to a smooth path to avoid interference or motion irregularities.

The present invention divides the maximum working space of the center point of the seat cushion into units of 10 mm (micrometers), and divides the working space of the seat cushion into, for example, 2,028 position points, but contains many points which are not feasible or desirable to avoid. When the working space is planned to move the traverse path of the seat cushion, the present invention presets the following three conditions:

(1) Before the seat cushion is adjusted for vertical height, the left and right adjustment of the center point of the seat cushion ( y- axis coordinate) and the front and rear roll angle of the seat cushion must be zeroed first.

(2) Before the seat cushion is traversed left and right, the roll angle of the seat cushion must be zeroed first, and the height of the seat cushion must remain unchanged during the process (the x- axis and z- axis coordinates of the seat center point must remain unchanged).

(3) When the seat cushion is tumbling forward and backward, the left and right adjustment of the center point of the seat cushion ( y- axis coordinate) must be reset to zero first.

Please refer to FIG. 5 and FIG. 6. FIG. 5 illustrates partial coordinate data of a feasible space range of the seat cushion according to the embodiment of the present invention. 6 is a schematic view showing a feasible space range of a seat cushion according to an embodiment of the present invention. In Fig. 5, the center point coordinates of the seat cushion are represented by a three-dimensional orthogonal coordinate system (x, y, z). Under the above three conditions, Figure 5 shows the feasible working space range of the center point of the seat cushion. For example, when the coordinates of the center point of the seat cushion are at (0, 0, 0), the maximum value of the leftward (or right) traverse is 130mm, and the reversible angle range is -15°~15°; the height of the center point of the seat cushion is upward or downward. When adjusting, the range of left and right traverse and flip angle of the seat cushion is gradually reduced; when the seat cushion is at the highest or lowest position (z=±65mm), the left and right traverse and flip angle ranges of the seat cushion are all zero. Figure 6 shows the feasible working space (hatched part) of the seat cushion. When the seat cushion is adjusted for vertical height, the front and rear movements will change accordingly, that is, the center point x coordinate and the z coordinate of the seat cushion are dependent, so Figure 5 The working point of the center point of the pad does not need to consider the center point x coordinate.

After planning the feasible working space of the center point of the seat cushion, the z- axis direction of the feasible working space is divided into 13 positions for vertical height adjustment in units of 10 mm per unit; 13 y- axis traversable ranges for vertical height adjustment position can be divided into a unit of 10mm per 10mm, and a total of 243 positions for lateral traverse adjustment (including 13 positions with zero traverse to zero) In terms of front and rear roll adjustment, according to the above rule (3), the left and right adjustment of the center point of the seat cushion ( y- axis coordinate) must be first zeroed, according to the range of the reversible angle of the 13 vertical height adjustment position points, Every 5° is a unit, and 61 points can be divided for front and rear roll adjustment (including 11 position points with zero roll angle), plus (-30,0,65) and (30,0,-65 ) These two position points (the highest and lowest of the vertical height). Adding three types of position points that can be used for seat cushion adjustment, deducting the position of repeated calculation, there are 295 position points in the feasible working space that meet the above three conditions (as shown in Figure 6), that is, the user can control the seat cushion. All work locations reached. The number of position points in the work space may vary depending on the overall mechanism of the seat mechanism 100. The above 295 position points are merely examples, and the present invention is not limited thereto.

The position points in the workspace and the lengths of their corresponding variable length links 141-144 are pre-calculated and stored, while the feasible action paths are pre-planned. For example, as shown in FIG. 6, if the current position of the movable plate 120 is (0, 0, 0), the target position point to be reached is (x, 20, 60), and the moving path can be set to 610 or 620. If the movable plate 120 is moved to the target position point via the moving path 610, the variable length links 141-144 adjust the length one by one according to the reference coordinates on the moving path 610, so that the movable plate 120 reaches each reference coordinate in the path. Then adjust to the target location point. For example, the movable plate 120 first completes the adjustment action to the reference coordinate 611 and then adjusts to the position of the next reference coordinate 612. By analogy, the movable plate 120 is moved along the moving path 610 to the target position point (x, 20, 60). Similarly, if it is selected to move to the target position via the moving path 620, the movable plate 120 is gradually adjusted to the target reference point (x, 20, 60) along the reference coordinate on the moving path 620.

When the user rides on the seat cushion, through the perception of the external environment and the user's comfortable posture, the seat cushion is adjusted to adjust the vertical height, the left and right traverse, and the front and rear tumbling, so that the seat cushion reaches a pre-planned position in the feasible working space. When the seat cushion is moved, the embodiment adjusts the variable length links 141 to 144 by using the stored information in advance, so that the seat cushion can be moved to a desired position according to a pre-planned path and avoid excessive tilt or jitter. A steady state is produced.

In addition, in the user's operation flow, the embodiment provides a user interface and its operation principle. FIG. 7 is a schematic diagram of the user interface (control panel) of the embodiment, including upper, lower, left, and right adjustment buttons and a rotation button, which allows the user to rotate the seat position and angle. In terms of operation, you need to follow the following principles:

(1) It is not possible to perform two or more adjustment actions at the same time. Pressing more than two button seats at the same time will not operate. Before the previous adjustment action has been completed, if the other buttons are pressed, the latter adjustment action is invalid.

(2) When adjusting the vertical height or rolling forward and backward, if the left and right traverse of the seat cushion is not zero, it will automatically return to zero first, and then perform the action to be adjusted.

(3) When performing the adjustment vertical height or the left and right traverse, if the seat roll roll angle is not zero, it will automatically return to zero first, and then perform the action to be adjusted.

Under the aforementioned plan, the movement of the seat cushion in the feasible working space is based on a pre-planned and unique path to ensure safety and stability. The invention writes the planned path in the feasible working space in the four-axis Stewart platform control program, and the 295 position points that have been divided in the feasible working space are also numbered one by one, and the corresponding points of each position point are calculated. The amount of elongation of the four variable length links 141 to 144 is established as a position table and written in the program. To move to the desired position, the program only needs to control the elongation of the four variable length links 141-144 without the need for inverse kinematics calculations. In this embodiment, the distance that the seat cushion moves is 10 mm each time (the distance from each position point to the next adjacent position point is 10 mm, which does not include the position of the roll), and each variable length link changes each time. The length will not exceed 20mm. After the variable length link is actuated at the same time, it can also approach the effect of simultaneous arrival. In the execution of the program, the control program of this embodiment proceeds in accordance with the following steps.

(1) After the system is started, the program automatically sets the preset initial position point to the target point to be reached.

(2) Wait for the input adjustment mode after moving the seat cushion to the initial position.

(3) If only one adjustment mode is input, proceed to the next step; if another adjustment mode is input during the input of one adjustment mode, the former is retained and the latter is deleted, and the next step is performed; for example, when moving to the target position During the process of inputting the adjustment mode, the adjustment mode input during the movement is deleted; if two or more adjustment modes are input at the same time, the input adjustment mode is deleted.

(4) Determine the number of the current location.

(5) If it is the number of the vertical height position point, the input adjustment mode can be any one of the three adjustment modes.

(6) If it is the number of the left and right traverse position points, if the input adjustment mode is traversable left and right, it will start to judge the number of the position to be reached; if the input adjustment mode is vertical height and roll forward and backward, it will be changed to Adjust the left and right traverse and start to judge the number of points to be reached.

(7) If it is the number of the front and rear roll position points, if the input adjustment mode is roll back and forth, it will judge the number of the position to be reached; if the input adjustment mode is vertical height and left and right traverse, it will be adjusted to roll before and after. And begin to judge the number of points to be reached.

(8) After judging the number of the position point to be reached, find the extension corresponding to each variable length link of the number (position point) from the position table already written in the program, and output it to the corresponding variable Length link.

It should be noted that the flow of the above control program is only an exemplary embodiment of the present invention, and the details of the control flow may be adjusted according to different design requirements, and the present invention is not limited.

As can be seen from the above, the seat mechanism 100 of the present invention has the functions of assisting the user to move and adjust the seat, and has a user-friendly operation interface, which can facilitate the user to communicate with the outside world. The sensing device and the wireless transmission device on the seat mechanism 100 can achieve the effect of telemedicine. The data processing and signal transmission in the seat mechanism 100 can be performed by a computer as long as the system is integrated in the seat mechanism 100, and the present invention does not limit the manner of data processing.

In addition, the joints at both ends of the linear brakes 141 to 144 need to have a multi-directional rotation function, and a ball joint or a universal joint can be used according to design requirements. For example, one end of the linear brake 141 can be connected to the movable plate 120 by a universal joint, and the other end can be used. The ball joint is connected to the mount 110. The present invention does not limit the form of the joint used at both ends of the linear brake 141. The linear brakes 141-144 can be replaced with adjustable length links, and the invention does not limit the form and construction of the links as long as the length can be adjusted.

In summary, the present invention utilizes a four-axis seat mechanism, so that the seat cushion of the electric wheelchair can have four degrees of freedom adjustment functions such as left and right traverse, height adjustment, back and forth movement and flipping, thereby allowing the user to use It is more convenient when using an electric wheelchair.

Although the preferred embodiments of the present invention have been disclosed as above, the present invention is not limited to the above-described embodiments, and any one of ordinary skill in the art can make some modifications without departing from the scope of the present invention. The scope of protection of the present invention should be determined by the scope of the appended claims.

100. . . Seat mechanism

110. . . Fixing frame

112. . . Base

114. . . Side stand

116, 118. . . Limiter

11a, 11b, 11c, 11d. . . contact

12a, 12b, 12c, 12d. . . contact

116a. . . Bearing bevel

120. . . Movable plate

141~144. . . Linear brake

141a. . . Ontology

141b. . . Axial rod

151~154. . . Ball joint

161~164. . . Universal joint

171~174. . . wheel

300. . . McKellen Wheel

311, 411, 421, 431, 441. . . Free roller

400. . . Seat mechanism

410~440. . . McKellen Wheel

610, 620. . . Moving path

611, 612. . . Reference coordinates

1 is a schematic view of a Stadford platform seat mechanism of a smart robotic wheelchair according to an embodiment of the present invention.

FIG. 2 is a schematic view of the limiting member 116 according to the embodiment.

FIG. 3A and FIG. 3B are schematic diagrams showing the structure of the McLaren wheel.

FIG. 4 is a schematic diagram showing the arrangement of the McLaren wheel set.

FIG. 5 is a partial coordinate view of a feasible space range of a seat cushion according to an embodiment of the present invention.

6 is a schematic view showing a feasible space range of a seat cushion according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of the user interface (control panel) of the embodiment.

100. . . Seat mechanism

110. . . Fixing frame

112. . . Base

114. . . Side stand

116, 118. . . Limiter

11a, 11b, 11c, 11d. . . contact

12a, 12b, 12c, 12d. . . contact

120. . . Movable plate

141~144. . . Linear brake

141a. . . Ontology

141b. . . Axial rod

151~154. . . Ball joint

161~164. . . Universal joint

171~174. . . wheel

Claims (10)

A smart robotic wheelchair, the Shiduhua platform seat mechanism comprises: a movable plate; a fixed frame having a first contact, a second contact, a third contact and a fourth contact, wherein The first contact and the second contact are located above the movable plate, the third contact and the fourth contact are located below the movable plate; a first variable length link, the variable length a first end of the connecting rod is pivotally connected to the first joint, a second end of the variable length connecting rod is pivotally connected to the movable plate; a second variable length connecting rod, the second variable length a first end of the connecting rod is pivotally connected to the second joint, a second end of the second variable length connecting rod is pivotally connected to the movable plate; a third variable length connecting rod, the third variable a first end of the length link is pivotally connected to the movable plate, a second end of the third variable length link is pivotally connected to the third contact; and a fourth variable length link, the fourth a first end of the variable length link is pivotally connected to the movable plate, and a second end of the fourth variable length link is pivotally connected to the fourth contact; wherein, the position of the movable plate The first to fourth lines with a change in length of the variable length link. The Stewart platform seat mechanism according to claim 1, wherein each of the first to fourth variable length links has a universal joint at each end thereof to respectively pivot Connected to the movable plate and the fixed frame. The Stewart platform seat mechanism according to claim 1, wherein each of the first to fourth variable length links has a ball joint at each end of the variable length link to respectively pivotally connect The movable plate and the fixing frame. The Stewart platform seat mechanism according to claim 1, wherein the fixing frame has a first limiting member and a second limiting member, respectively disposed on the first contact and the second connection Below the point, the first limiting member has a first bearing slope to limit the inclination angle of the first variable length link; the second limiting member has a second bearing slope to limit the second The angle of inclination of the variable length link. The Stewart platform seat mechanism according to claim 1, wherein the fixing frame has a base and a side stand, and the first contact and the second contact are located on the side stand, The third contact and the fourth contact are located on the base. The Stewart platform seat mechanism according to claim 5, wherein the movable plate is located at one side of the side stand, and the first variable length link and the second variable length link are respectively pivoted Connected to a first side of the movable plate. The Stewart platform seat mechanism of claim 6, wherein the third variable length link and the fourth variable length link are respectively pivotally connected to the movable plate relative to the first side a second side of the side. The Stewart platform seat mechanism as described in claim 1 further includes: a Mecanum Wheel set disposed below the fixed frame; wherein each of the variable length links is respectively Having a body and an axial rod, the body is coupled to the axial rod and the axial rod is displaced along an axial direction, wherein the body of each variable length link is pivotally connected to the fixed frame, the shaft One end of the rod is pivotally connected to the movable plate; wherein each of the variable length links is a linear brake, and the holder is L-shaped. The Stewart platform seat mechanism according to claim 1, wherein when the lengths of the first variable length link and the second variable length link are increased and the third variable length link is When the length of the fourth variable length link is shortened, the height of the movable plate is lowered; when the length of the first variable length link and the second variable length link is shortened and the third variable length link is As the length of the fourth variable length link increases, the height of the movable plate rises; when the first variable length link, the second variable length link, the third variable length link, and The length of the fourth variable length link is simultaneously increased, and the length of the second variable length link is greater than the first variable length link and the length of the fourth variable length link is greater than the third variable The length of the link is traversed toward the side of the first variable length link and the third variable length link; when the first variable length link, the second variable length is connected The rod, the third variable length link, and the length of the fourth variable length link are simultaneously increased, and the When the length of the variable length link is greater than the second variable length link and the length of the third variable length link is greater than the fourth variable length link, the movable plate is connected to the second variable length The rod traverses the side direction of the fourth variable length link. A control method for a Stewart platform seat mechanism of a smart robot wheelchair as described in claim 1 of the patent application, comprising: a plurality of position points achievable according to the movable plate and corresponding first to first Corresponding relationship between the lengths of the four variable length links establishes a working space having reference coordinates corresponding to each of the position points and corresponding four variable length link length values; according to a current position point and a target The position point establishes a moving path from the working space, the moving path is composed of adjacent reference coordinates; and adjusts the lengths of the first to fourth variable length links one by one according to the reference coordinates corresponding to the moving path And moving the movable plate to the target position point via a position point corresponding to the movement path.