Multidirectional tilting quad-rotor unmanned aerial vehicle

Abstract

The invention belongs to the field of unmanned aerial vehicles, particularly relates to a multidirectional tilting quad-rotor unmanned aerial vehicle, and aims to solve the problem that the structural stability and maneuverability of a heavy-load unmanned aerial vehicle in the prior art are difficult to balance. The unmanned aerial vehicle comprises a vehicle body, a rotor wing tilting device and a driving device. The aircraft body is composed of a top plate, a bottom plate, a supporting column, a movable ring, a fixed ring and four rotor wing assemblies, and the rotor wing assemblies achieve tilting through main arms, sliding bases and steering bases. The rotor wing tilting device adopts a gear and rack transmission mechanism, and four rotor wings are driven to tilt synchronously through a movable plate. The driving device adopts a double-driver design, a first driver controls the swing rod to swing, and a second driver drives the first driver to rotate. The movable structure supports oblique movement of the movable plate, and multi-direction tilting of the rotor wing assembly is achieved. By optimizing the layout of the tilting mechanism, the flight stability and flexibility are improved while the bearing capacity is ensured, and the unmanned aerial vehicle is suitable for heavy-load application scenes such as logistics transportation and agricultural spraying.

Description

Technical Field

[0001] This invention belongs to the field of unmanned aerial vehicle (UAV) technology, specifically relating to a multi-directional tilting quadcopter UAV. Background Technology

[0002] With the continuous advancement of technology, drone technology is becoming increasingly mature, and its applications are expanding. The maneuverability and flight stability of quadcopter drones mainly depend on changes in rotor speed. However, simply adjusting the speed to change direction results in poor maneuverability and high rotor drag. Therefore, tilt rotors have become an important direction for improving the performance of quadcopter drones.

[0003] Currently, many drones typically equip each rotor with one or two motors for individual control to achieve rotor tilting. This design results in low motor utilization, unnecessarily increasing the drone's weight, and consequently affecting its range and flight efficiency. In contrast, the invention patent application "A Multi-directional Tilting Quadcopter" (CN 110341947 B) discloses a method for tilting rotors, achieving tilting of four rotors in both the forward and left / right directions by using a gimbal control stick, ball bearings, transmission brackets, directional control sticks, drive sticks, and drive motor modules. However, the gimbal structure relies on spherical contact and bearing fit, concentrating the load in a localized area between the ball joint and the bearing. With a small contact area, long-term use can lead to reduced transmission accuracy due to wear and increased clearance. Under heavy loads, the contact stress between the ball joint and the bearing increases sharply, easily causing micro-deformation or loosening at the gimbal connection, leading to decreased flight stability and even structural fatigue fracture, shortening service life. Furthermore, the gimbal structure connects individual rotors, failing to effectively distribute the load and lacking the collaborative load-bearing capacity and practicality of the overall frame. Summary of the Invention

[0004] The present invention aims to provide a multi-directional tilting quadcopter drone to solve the problem of balancing structural stability and maneuverability in existing heavy-load drones.

[0005] To achieve the above objectives, the present invention provides a multi-directional tilting quadcopter unmanned aerial vehicle, comprising: The fuselage includes a top plate, a bottom plate, several support columns, a movable ring, a fixed ring, and four rotor assemblies. One end of each support column is fixedly connected to the top plate, and the other end is fixedly connected to the bottom plate. The movable ring is located between the top plate and the bottom plate, and the polygon formed by the support columns as vertices is smaller than the inner circle size of the movable ring. The fixed ring is fixed to the bottom plate, and four fixed arms are evenly distributed around the circumference of the fixed ring. Four movable arms are evenly distributed around the circumference of the movable ring. The fixed arms are parallel to the movable arms, and the outer ends of both the fixed arms and the movable arms are rotatably connected to steering seats. Each rotor assembly includes a rotor motor, a rotor, and a main arm. The rotor motor is mounted on the top of the main arm, and the rotor is mounted on the output end of the rotor motor. A slide is also hinged to the steering seat of the movable arm. The middle part of the main arm is slidably connected in the slide, and the bottom of the main arm is hinged to the steering seat on the movable arm. A limiting structure is provided on the part of the main arm located between the fixed arm and the movable arm to restrict the slide from sliding towards the fixed arm. The rotor tilting device includes four racks, a movable plate, four gears, and four drive shafts. The movable plate is located inside the fixed ring. The four racks are all fixed on the movable plate and correspond to the positions of the four movable arms. The four drive shafts pass through the four fixed arms along their axes and are rotatably connected to the fixed arms. The outer ends of the drive shafts are connected to the steering seats on the fixed arms. The four gears are respectively installed on the inner ends of the four drive shafts and mesh with the four racks. A slide cylinder is installed in the middle of the movable plate. A slide column is slidably connected inside the slide cylinder, and a swing rod is hinged to the top of the slide column. The driving device includes a first driver that drives the swing arm to swing and a second driver that drives the first driver to rotate, the second driver being mounted on the top plate.

[0006] The working principle and beneficial effects of this scheme are as follows: The first driver drives the second driver to rotate, and the second motor drives the pendulum to swing, thereby realizing the swing of the pendulum in the forward, backward, left, right, and diagonal directions. The pendulum is hinged to the top of the sliding column, which slides up and down inside the sliding cylinder. The sliding cylinder is fixed to the movable plate, thus converting the reciprocating circular motion of the pendulum into the planar linear motion of the movable plate. When the pendulum swings in the forward, backward, left, and right directions, the movable plate moves in the forward, backward, left, and right directions. The rack on the movable plate drives two oppositely arranged gears to rotate, and two other oppositely arranged gears slide on the rack. The rotating gears drive the connected transmission shaft to rotate together, and the rotating transmission shaft drives the connected steering seat to rotate. The rotor assembly connected to the rotating steering seat tilts. Through the cooperation of the steering seat, sliding seat, movable ring, and movable arm, under the action of the tilting of two opposite rotor assemblies, the other two opposite rotor assemblies also tilt in the same direction. Ultimately, the rotor assemblies tilt synchronously, avoiding flight instability caused by differences in the tilt angle of a single rotor, and increasing the flexibility of the UAV.

[0007] (1) The drive shaft is directly installed inside the fixed arm, which has strong anti-torsion capacity. The load is distributed through the movable ring, fixed ring and support column to avoid local overload and is suitable for heavy loads. (2) Through the sliding connection between the main arm and the slide and the limiting structure of the slide, the flexibility of the rotor assembly tilting is ensured, and the movement of the main arm is further constrained to prevent tilting overload. (3) The drive unit links the four rotor assemblies through the gear and rack mechanism, which reduces mechanical complexity, reduces the number of motors, reduces power consumption and weight, and the gear and rack mesh without gap, resulting in fast response and precise control.

[0008] The solution of this invention is suitable for application scenarios with high load requirements and stringent requirements for flight stability and maneuverability, such as logistics transportation and agricultural spraying.

[0009] Optionally, the first driver and the second driver include one of a servo motor, a hydraulic motor, and a dual-axis servo motor.

[0010] Optionally, the drive device is provided with a bottomless mounting box, a first driver is mounted on the side of the mounting box, the output end of the first driver extends into the mounting box, one end of the lever is connected to the output end of the first driver, and the other end extends outside the bottom surface of the mounting box.

[0011] Optionally, the second driver of the drive device has two output ends, each with a rudder disk. U-shaped brackets are provided on both sides of the second driver. The opening of the left U-shaped bracket is fixedly connected to the two rudder disks, and the opening of the right U-shaped bracket is fixedly connected to the two surfaces of the output ends of the second driver. The left U-shaped bracket is fixedly connected to the top surface of the mounting box, and the right U-shaped bracket is fixedly connected to the top plate.

[0012] Optionally, the width of the rack is greater than or less than the width of the gear. The increased width of the rack or gear serves as compensation for the meshing of the gear and rack, allowing the gear and rack to maintain relative sliding while remaining meshed.

[0013] Optionally, the slide block is equipped with a sliding bearing. This reduces sliding friction between the slide block and the main arm, ensuring smooth tilting motion.

[0014] Optionally, the limiting structure can be configured as a stop or a pin. The stop is a block-shaped component fixed to the main arm, located between the fixed arm and the movable arm, and restricts the slider from sliding towards the fixed arm. The pin is a removable pin, and the main arm has several pin through holes. The pin is inserted into the pin through holes to restrict the slider from sliding towards the fixed arm. The pin can be selectively inserted into different pin through holes to adjust the distance between the fixed arm and the movable arm.

[0015] Optionally, the fixed arm, drive shaft, and movable arm are provided with movable structures. These movable structures include pin structures, cross-hinged structures, and ball-joint structures. The pin structures are located on the upper and lower sides of the fixed arm, and the pin structures and cross-hinged structures are aligned on the same vertical line. The pin structures on the upper and lower sides of the fixed arm allow the portion of the fixed arm connected to the steering seat to swing horizontally. The cross-hinged structure on the drive shaft not only transmits rotation to the steering seat but also allows the portion of the drive shaft connected to the steering seat to swing horizontally. The ball-joint structure on the movable arm allows the portion of the movable arm connected to the steering seat to rotate in any direction. The pin structures and cross-hinged structures being aligned on the same vertical line allow the fixed arm and drive shaft to swing synchronously without interfering with each other.

[0016] Optionally, the distance between the movable structure and the steering seat is less than the distance between the movable structure and the fixed ring. This prevents the rotor assembly from colliding with the main body of the UAV during tilting.

[0017] Optionally, the movable ring and the fixed ring are one or more of the following shapes: circle, rectangle, rounded rectangle, regular polygon, or irregular shape. Attached Figure Description

[0018] Figure 1 This is an overall rendering of a multi-directional tilting quadcopter drone according to Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the rotor tilting device of a multi-directional tilting quadcopter UAV in a static state according to Embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the motion state of the rotor tilting device of a multi-directional tilting quadcopter drone according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of a drive device for a multi-directional tilting quadcopter drone according to Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the sliding column and the ball joint of a multi-directional tilting quadcopter UAV in Embodiment 2 of the present invention; Figure 6 This is a side view of the active structure of a multi-directional tilting quadcopter UAV according to Embodiment 3 of the present invention. Detailed Implementation

[0019] The following detailed description illustrates the specific implementation method: The markings in the accompanying drawings include: top plate 1, bottom plate 2, movable plate 21, rack 22, gear 23, drive shaft 24, cross hinge structure 241, slide cylinder 25, slide column 26, swing arm 27, support column 3, fixed ring 4, fixed arm 41, pin structure 411, steering seat 42, movable ring 5, movable arm 51, ball hinge structure 511, main arm 6, rotor motor 61, rotor 62, slide seat 63, stop block 64, servo motor 7, mounting box 71, dual-axis servo motor 8, servo disc 81, U-shaped bracket 82.

[0020] Example 1 This embodiment is basically as follows: Figure 1 , 2 The diagram shows a multi-directional tilting quadcopter unmanned aerial vehicle (UAV). The fuselage structure consists of a top plate 1 and a bottom plate 2, fixedly connected by four support columns 3 to form a rigid frame. A fixed ring 4 is a circular ring fixed to the bottom plate 2, with four circumferentially distributed fixed arms 41. Each fixed arm 41 has a steering seat 42 at its end. A movable ring 5 is a rounded rectangle located between the top plate 1 and the bottom plate 2, slightly larger than the quadrilateral formed by the support columns 3. The movable ring 5 also has four circumferentially distributed movable arms 51, parallel to the fixed arms 41, and also has a steering seat 42 at its end. Each rotor assembly includes a main arm 6, a rotor motor 61, and a rotor 62. The rotor motor 61 is mounted on the top of the main arm 6, and the output end of the rotor motor 61 is connected to the rotor 62, driving the rotor 62 to rotate. The bottom of the main arm 6 is hinged to the steering seat 42 at the end of the fixed arm 41. The main boom 6 is slidably connected to the slide block 63 in the middle. The slide block 63 contains a sliding bearing to reduce friction. The slide block is hinged to the steering seat 42 of the movable boom 51. A limiting structure is set as a stop block 64, which is located on the main boom 6 between the fixed boom and the movable boom, restricting the slide block 63 from sliding towards the fixed boom 41. Figure 2 , Figure 3 As shown, the movable plate 21 is located inside the fixed ring 4, and four racks 22 are fixed thereon, each meshing with one of the four gears 23. The gears 23 are mounted on the drive shaft 24, which passes through the fixed arm 41 and connects to the steering seat 42. The slide cylinder 25 is fixed to the movable plate 21, and a sliding column 26 is slidably connected inside. A rocker arm 27 is hinged to the top of the sliding column 26. The first driver is a servo motor 7 with a brake device. The servo motor 7 drives the rocker arm 27 to swing, thereby controlling the movable plate 21 to perform planar linear motion on the base plate 2. Figure 4As shown, the drive unit is equipped with a bottomless mounting box 71. The servo motor 7 is mounted on the side of the mounting box 71, and the output end of the servo motor 7 extends into the mounting box 71. One end of the swing arm 27 is connected to the output end of the servo motor 7, and the other end of the swing arm 27 extends beyond the bottom surface of the mounting box 71. The second driver is a dual-axis servo motor 8. The dual-axis servo motor 8 has two servo disks 81 at its two output ends. U-shaped brackets 82 are provided on both sides of the dual-axis servo motor 8. The opening of the left U-shaped bracket 82 is fixedly connected to the two servo disks 81 respectively, and the opening of the right U-shaped bracket 82 is fixedly connected to the two surfaces of the output end of the dual-axis servo motor 8 respectively. The left U-shaped bracket 82 is fixedly connected to the top surface of the mounting box 71, and the right U-shaped bracket 82 is fixedly connected to the top plate 1. When the servo motor 7 drives the rocker arm 27 to swing in the front-to-back direction, the dual-axis servo motor 8 drives the servo motor 7 to rotate 90 degrees, which allows the rocker arm 27 to swing in the left-to-right direction; when the dual-axis servo motor 8 drives the servo motor 7 to rotate 180 degrees, the rocker arm 27 still swings in the front-to-back direction; when the angle of rotation of the servo motor 7 driven by the dual-axis servo motor 8 is not a multiple of 90 degrees, the rocker arm 27 swings in the diagonal direction.

[0021] The specific implementation process is as follows: When in use, the servo motor 7 is started. When the servo motor 7 drives the swing arm 27 to swing forward, the swing arm 27 pushes the slide cylinder 25, causing the movable plate 21 to move forward horizontally. At this time, the gears 23 on the front and rear sides do not rotate, while the racks 22 on the left and right sides drive the gears 23 on the left and right sides to rotate in the opposite direction, driving the transmission shafts 24 and the steering seat 42 on the left and right sides to rotate, causing the rotor assemblies on the left and right sides to tilt backward. Through the cooperation of the steering seat 42, the slide 63, the movable ring 5, and the movable arm 51, under the action of the rotor assemblies on the left and right sides tilting backward, the rotor assemblies on the front and rear sides also tilt backward, realizing that the four rotor assemblies tilt backward synchronously, ensuring flight stability.

[0022] Similarly, when the pendulum 27 swings backward, the four rotor components tilt forward synchronously.

[0023] When the rotor assembly needs to tilt to the left or right, the dual-axis servo motor 8 is activated to drive the servo motor 7 to rotate 90 degrees, so that the servo motor 7 drives the swing arm 27 to swing in the left and right directions.

[0024] When the swing arm 27 swings to the left, it pushes the slide cylinder 25, causing the movable plate 21 to move to the left. At this time, the gears 23 on the left and right sides do not rotate, while the racks 22 on the front and rear sides drive the gears 23 on the front and rear sides to rotate in the opposite direction, causing the transmission shafts 24 and steering seats 42 on the front and rear sides to rotate, thus causing the rotor assemblies on the front and rear sides to tilt to the right. Through the cooperation of the steering seat 42, slide 63, movable ring 5, and movable arm 51, the rotor assemblies on the left and right sides tilt to the right under the action of the rotor assemblies on the front and rear sides tilting to the right, realizing that all four rotor assemblies tilt to the right synchronously.

[0025] Similarly, when the pendulum 27 swings to the right, the four rotor components tilt to the left in sync.

[0026] Example 2 The difference between this embodiment and Embodiment 1 is that: Figure 5 As shown, the top of the sliding column 26 has a ball joint swing arm 27. The width of the rack 22 is greater than or less than the width of the gear 23, allowing the gear 23 and rack 22 to maintain meshing while also sliding relative to each other. The limiting structure is a pin structure, with several pin through holes on the main arm 6. Inserting the pin into the pin through holes restricts the sliding block 63 from sliding towards the fixed arm 41. The position of the inserted pin through hole can also be selected to adjust the distance between the fixed arm 41 and the movable arm 51. The second drive is a hydraulic motor that drives the first drive to rotate. The hydraulic motor has strong power and precise rotation control, making it especially suitable for drones that require heavy loads.

[0027] Example 3 The difference between this embodiment and Embodiment 1 is that: Figure 6 As shown, the fixed arm 41, the drive shaft 24, and the movable arm 51 are provided with movable structures. The movable structures are respectively configured as a pin structure 411, a cross hinge structure 241, and a ball hinge structure 511. The pin structure 411 is provided on the upper and lower sides of the fixed arm 41. The pin structure 411 and the cross hinge structure 241 are arranged on the same vertical line, and the distance between the movable structure and the fixed ring 4 is twice the distance between the movable structure and the steering seat 42. The pin structures 411 on the upper and lower sides of the fixed arm 41 allow the portion of the fixed arm 51 connected to the steering seat 42 to swing in the horizontal plane; the cross hinge structure 241 on the drive shaft 24 not only transmits rotation to the steering seat 42, but also allows the portion of the drive shaft 24 connected to the steering seat 42 to swing in the horizontal plane; the ball hinge structure 511 on the movable arm 51 allows the portion of the movable arm 51 connected to the steering seat 42 to rotate in any direction; the pin structures 411 and the cross hinge structure 241 are arranged on the same vertical line, allowing the fixed arm 41 and the drive shaft 24 to swing synchronously without interfering with each other. The movable structures on the fixed arm 41, drive shaft 24, and movable arm 51 ensure that the rotor assembly can also tilt when the swing arm 27 swings in the oblique direction.

[0028] The specific implementation process is as follows: When in use, the servo motor 7 is started. When the servo motor 7 drives the swing arm 27 to swing to the right front, the swing arm 27 pushes the slide cylinder 25, causing the movable plate 21 to move horizontally to the right front. At this time, under the action of the rack 22 on the movable plate 21, the right and left gears 23 rotate backward, and the front and rear gears 23 rotate to the left. The right gear 23 rotates backward, driving the right drive shaft 24 and the steering seat 42 to rotate backward. Under the action of the backward rotational force, the part of the drive shaft 24 connected to the steering seat 42 and the part of the fixed arm 41 connected to the steering seat 42 swing backward. Under the combined action of the ball joint structure 511 on the slide 63 and the backward pulling force of the movable arm 51, the right rotor assembly tilts to the left rear. Similarly, the left gear 23 rotates backward, and the left rotor assembly tilts to the left rear. The front gear 23 rotates to the left, causing the front drive shaft 24 and steering seat 42 to rotate to the left. Under the action of the leftward rotational force, the part of the drive shaft 24 connected to the steering seat 42 and the part of the fixed arm 41 connected to the steering seat 42 swing to the left. Under the combined action of the ball joint structure 511 on the slide 63 and the backward pulling force of the movable arm 51, the front rotor assembly tilts to the left rearward. Similarly, the rear gear 23 rotates to the left, and the rear rotor assembly tilts to the left rearward. Finally, when the swing arm 27 swings to the right front, all four rotor assemblies tilt synchronously to the left rearward.

[0029] Similarly, when the pendulum 27 swings to the left front, the four rotor components tilt to the right rear simultaneously; when the pendulum 27 swings to the right rear, the four rotor components tilt to the left front simultaneously; when the pendulum 27 swings to the left rear, the four rotor components tilt to the right front simultaneously.

[0030] The above are merely embodiments of the present invention. The invention is not limited to the fields covered by these embodiments. Commonly known structures and characteristics in the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are able to access all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A multi-directional tilting quadcopter unmanned aerial vehicle, characterized in that, include: The fuselage includes a top plate, a bottom plate, several support columns, a movable ring, a fixed ring, and four rotor assemblies. One end of each support column is fixedly connected to the top plate, and the other end is fixedly connected to the bottom plate. The movable ring is located between the top plate and the bottom plate, and the polygon formed by the support columns as vertices is smaller than the inner circle size of the movable ring. The fixed ring is fixed to the bottom plate, and four fixed arms are evenly distributed around the circumference of the fixed ring. Four movable arms are evenly distributed around the circumference of the movable ring. The fixed arms are parallel to the movable arms, and the outer ends of both the fixed arms and the movable arms are rotatably connected to steering seats. Each rotor assembly includes a rotor motor, a rotor, and a main arm. The rotor motor is mounted on the top of the main arm, and the rotor is mounted on the output end of the rotor motor. A slide is also hinged to the steering seat of the movable arm. The middle part of the main arm is slidably connected in the slide, and the bottom of the main arm is hinged to the steering seat on the movable arm. A limiting structure is provided on the part of the main arm located between the fixed arm and the movable arm to restrict the slide from sliding towards the fixed arm. The rotor tilting device includes four racks, a movable plate, four gears, and four drive shafts. The movable plate is located inside the fixed ring. The four racks are all fixed on the movable plate and correspond to the positions of the four movable arms. The four drive shafts pass through the four fixed arms along their axes and are rotatably connected to the fixed arms. The outer ends of the drive shafts are connected to the steering seats on the fixed arms. The four gears are respectively installed on the inner ends of the four drive shafts and mesh with the four racks. A sliding cylinder is installed in the middle of the movable plate, and a sliding column is slidably connected inside the sliding cylinder. A swing rod is hinged to the top of the sliding column. The driving device includes a first driver that drives the swing arm to swing and a second driver that drives the first driver to rotate, the second driver being mounted on the top plate.

2. The multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The first driver and the second driver include one of a servo motor, a hydraulic motor, and a dual-axis servo motor.

3. The multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The drive device is provided with a bottomless mounting box. The first driver is mounted on the side of the mounting box, and the output end of the first driver extends into the mounting box. One end of the lever is connected to the output end of the first driver, and the other end extends outside the bottom surface of the mounting box.

4. A multi-directional tilting quadcopter UAV according to claim 3, characterized in that: The second driver of the drive device has two output ends, each with a rudder disk. U-shaped brackets are provided on both sides of the second driver. The opening of the left U-shaped bracket is fixedly connected to the two rudder disks, and the opening of the right U-shaped bracket is fixedly connected to the two surfaces of the output ends of the second driver. The left U-shaped bracket is fixedly connected to the top surface of the mounting box, and the right U-shaped bracket is fixedly connected to the top plate.

5. A multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The width of the rack is greater than or less than the width of the gear.

6. A multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The slide block is equipped with a sliding bearing.

7. A multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The limiting structure is set as a stop or a pin.

8. A multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The fixed arm, drive shaft, and movable arm are provided with movable structures. The movable structures are respectively provided with pin structures, cross hinge structures, and ball hinge structures. The pin structures are provided on the upper and lower sides of the fixed arm, and the pin structures and cross hinge structures are provided on the same vertical line.

9. A multi-directional tilting quadcopter UAV according to claim 8, characterized in that: The distance between the movable structure and the steering seat is less than the distance between the movable structure and the fixed ring.

10. A multi-directional tilting quadcopter UAV according to claim 1, characterized in that: The movable ring and the fixed ring are one or more of the following shapes: circle, rectangle, rounded rectangle, regular polygon, or irregular shape.

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