Walking robot made from paper clips. Ten homemade robots

Walking robots are a class of robots that imitate the movement of animals or insects. Typically, robots use mechanical legs to move. Locomotion with the help of legs has millions of years of history. In contrast, the history of movement with the help of the wheel began from 10 to 7 thousand years ago. Wheeled travel is quite effective, but requires relatively smooth roads. Just look at an aerial photograph of a city or its suburbs to notice a network of intertwining roads.

Walking robots can move over rough terrain that is inaccessible to conventional wheeled vehicles. Walking robots are usually created for a similar purpose.

Advanced walking robots imitate the movements of insects, crustaceans, and sometimes humans. Bipedal robot designs are rare because they require complex engineering solutions to implement. I plan to cover a bipedal robot project in my next book with code name Pic-Robotics. In this chapter we will build a six-legged walking robot.

Using a model with six legs, we can demonstrate the famous tripod gait, that is, with support on three legs, which most creatures use. In the following illustrations, the dark circle indicates that the foot is firmly planted on the ground and supports the weight of the creature. A light circle means the leg is raised and in motion.

In Fig. Figure 11.1 shows our being in the “standing” position. All feet rest on the ground. From a position of “standing,” our being decides to move forward. To take a step, it lifts three of its legs (see light circles in Figure 11.2), resting its weight on the three remaining legs (dark circles). Notice that the legs supporting the weight (dark circles) are arranged in a tripod (triangle) shape. This position is stable and our being cannot fall. The other three legs (open circles) can and do move forward. In Fig. Figure 11.3 shows the moment of movement of the raised legs. At this point, the creature's weight shifts from stationary to moving legs (see Figure 11.4). Notice that the creature's weight is still supported by the triangular arrangement of the supporting legs. Then the other three legs are rearranged in the same way, and the cycle repeats. This method of transportation is called tripod gait, since the weight of the creature's body is supported at any given time by the triangular position of the supporting legs.

Rice. 11.1. Tripod gait. Initial position

Rice. 11.2. Tripod gait, first step forward

Rice. 11.3. Tripod gait, second movement, shifting the center of gravity

Rice. 11.4. Tripod gait, third movement

There are many models of small wind-up walking toys. These toy “pedestrians” move their legs up and down and back and forth using cam mechanisms. Although such designs are quite capable of “walking”, and some do so quite nimbly, our goal is to create a walking robot that does not use cam mechanisms to simulate stepping movement.

We will build a robot that simulates a tripod gait. The robot described in this chapter requires three servos to move. There are other six-legged and four-legged models of walking robots that require greater degrees of freedom in their legs. Accordingly, the presence more degrees of freedom requires more control mechanisms for each leg. If servomotors are used for this purpose, then two, three or even four motors will be required for each leg.

The need for such a number of servomotors (drives) is dictated by the fact that at least two degrees of freedom are required. One is for lowering and raising the leg, and the other is for moving it back and forth.

The walking robot we are going to make is a compromise in design and design and requires only three servos. However, even in this case, it provides movement using a tripod gait. Our design uses three lightweight HS300 servomotors (torque 1.3 kgf) and a 16F84-04 microcontroller.

Before we start constructing the robot, let's look at the finished robot shown in Fig. 11.5, and let’s analyze how the robot moves. The tripod gait, which is used in this design, is not the only possible one.

Rice. 11.5. Six-legged walker is ready for a walk

Two servomotors are attached to the front of the robot. Each of the servomotors controls the movement of the front and rear legs on the corresponding side of the robot. The front leg is attached directly to the servo motor rotor and is capable of swinging back and forth. The back leg is connected to the front leg using a rod. The pull allows the back leg to follow the back and forth movement of the front leg. The two central legs are controlled by a third servomotor. This servomotor rotates the central legs along the longitudinal axis at an angle of 20° to 30° clockwise and counterclockwise, which tilts the robot to the right or left.

Using the information about the leg drive mechanism, we will now look at how our robot will move. Let's look at fig. 11.6. We will start from the resting position. Each circle marks the position of a leg. As in the previous case, dark circles show the position of the supporting legs. Note that in the resting position the middle legs are not supporting legs. These legs are 3 mm shorter than the front and hind legs.

Rice. 11.6. Phases of hexapod movement

In position A, the central legs rotate clockwise at an angle of approximately 20° from central position. This causes the robot to tilt to the right. In this position, the robot's weight is supported by the right front and rear legs and the left center leg. This is the standard tripod position described above. Since the left front and left rear legs are “in the air”, they can be moved forward, as shown in Fig. 11.6, position B.

In position C, the central legs rotate counterclockwise at an angle of approximately 20° from the central position. This causes the robot to tilt to the left. In this position, the robot's weight is distributed between the left front and rear legs and the right middle leg. Now the right front and rear legs do not bear the load and can be moved forward, as shown in pos. D fig. 11.6.

In position E, the central legs return to the middle position. In this position, the robot “stands” upright and relies only on its front and back legs. In position F, the front and rear legs simultaneously move backward, and the robot moves forward, respectively. Then the cycle of movement is repeated.

This was the first walking method I tried to reproduce, and this system works. You can develop, improve, and construct other models of walking patterns that you can experiment with. I'll leave it to you to work out ways to walk backwards (reversing) and turning right and left. I will continue to improve this robot by adding sensors for walls and obstacles, as well as ways to move backwards and turn.

I took a sheet of aluminum measuring 200x75x0.8 mm as the basis for the “body” of the robot. The servomotors are attached to the front of the plate (see Figure 11.7). The markings of the holes for the servomotors should be copied from the drawing and transferred to a sheet of aluminum. Such copying will ensure the accuracy of the position of the holes for mounting the servomotors. Four 4.3 mm diameter holes are located slightly behind the centerline and are designed to mount the central servomotor. These four holes are offset to the right edge. This must be done so that the flange of the central servomotor is exactly in the center of the “body”. Two rear holes are designed for movable attachment of the hind legs.

Rice. 11.7. The base of the "body"

To mark the centers of holes for drilling, you must use a center punch. Otherwise, when drilling holes, the drill may “lead away”. If you don't have a punch, you can use a sharp nail as a good substitute.

The robot's legs are made of aluminum strip 12 mm wide and 3 mm thick (see Fig. 11.8). Four holes are drilled in the front legs. Two holes are drilled in the rear legs: one for the movable attachment, and the other for attaching the rod. Please note that the hind legs are 6 mm shorter than the front legs. This is because it is necessary to take into account the height of the servomotor flange, to which the front legs are attached, above the general level of the plate. Shortening the hind legs levels the platform.

Rice. 11.8. Front and rear leg design

After drilling the required holes, you need to bend the aluminum strip to the desired shape. Clamp the strip in a vice from the side of the drilled holes at a distance of 70 mm. Press the plate down and bend it at a 90° angle. It is best to press the plate directly next to the vise jaws. In this case, the plate will bend at an angle of 90° without the risk of bending the “lowest” part of the leg.

The central legs are made from one piece of aluminum (see Fig. 11.9). When attached to the robot, the central legs are 3 mm shorter than the front and rear legs. Thus, in the middle position they do not touch the ground. These legs are designed to tilt the robot to the right and left. When the central servomotor rotates, the legs tilt the robot at an angle of approximately ±20°.

Rice. 11.9. Middle legs

When making the central legs, in an aluminum strip measuring 3x12x235 mm, first three central holes are drilled for the servomotor flange. Then the aluminum strip is secured in a vice, and the jaws of the vice along the upper edge should fix the strip at a distance of 20 mm from the center of the strip. Clamp the strip with pliers approximately 12mm from the top edge of the vise. While maintaining the grip of the pliers, carefully twist the aluminum strip at a 90° angle. Perform the operation quite slowly, otherwise you can easily break the plate. Twist the plate on the other side in the same way.

After the 90° twist is done, additionally bend the plate in two places by 90°, as we did for the front and rear legs.

The front servos are attached to the aluminum base using 3mm plastic screws and nuts. I chose plastic screws because they can be bent slightly to accommodate small misalignments between the holes drilled in the plate and the servo mounting holes.

The legs are attached to the plastic flange of the servomotor. For this I used 2mm screws and nuts. When attaching the flange to the servo motor shaft, make sure that each leg can move back and forth at the same angle from the average perpendicular position.

The rod between the front and rear legs is made of a rod with a 3 mm thread (see Fig. 11.10). The original design has a rod length of 132mm center to center. The rod fits into holes on the robot's front and rear legs and can be secured with a few nuts.

Rice. 11.10. Detailed drawing of the hinge and rod

Before installing the traction, the robot's rear legs must be attached to the base. The rear leg mount is made from a 9.5mm threaded rivet and a machine screw. Detailed leg attachment is shown in Fig. 11.10. It is necessary to place plastic washers under the base, which will fill the space between the bottom of the base and the screw head. This design ensures that the leg is attached to the base without “dangling”. To reduce friction, you can use plastic washers. Do not use too many washers - this will cause excessive pressure on the foot against the surface of the base. The leg should rotate in the joint quite freely. In Fig. 11.11 and 11.12 show photographs of a partially assembled six-legged robot.

Rice. 11.11. Hexapod - ventral view. There are two servomotors in front

Rice. 11.12. Partially assembled hexapod with two front servos

To attach the central servomotor, you will need two L-shaped brackets (see Fig. 11.13). Drill appropriate holes in the aluminum strips and bend them at a 90° angle to create brackets. Attach two L-shaped brackets to the center servomotor using plastic screws and nuts (see Figure 11.14). Then attach the center servo assembly to the bottom of the base. Align the four holes on the base with the holes on the top of the L-brackets. Secure the pieces together using plastic screws and nuts. In Fig. 11.15 and 11.16 show photographs of the top and bottom views of the six-legged robot.

Rice. 11.13. Central Servo Motor Bracket

Rice. 11.14. Center motor assembly with mounting brackets and middle legs

Rice. 11.15. Hexapod - bottom view with three servos

Rice. 11.16. Hexapod assembled. The structure is ready for installation of electronic control

In Fig. Figure 11.17 shows a diagram for controlling servomotors using a PIC microcontroller. The servomotors and microcontroller are powered by a 6 V battery. The 6 V battery compartment contains 4 AA cells. The microcontroller circuit is assembled on a small breadboard. The battery compartment and circuitry are attached to the top of the aluminum base. Figure 11.5 shows the completed robot design, ready to “move.”

Rice. 11.17. Schematic diagram control of a six-legged robot

The 16F84 microcontroller controls the operation of three servomotors. Availability large number unused I/O buses and space for the program provide the opportunity to improve and modify the basic robot model.

‘Six-legged walking robot

‘Connections

‘Left servomotor Pin RB1

‘Right Servo Pin RB2

‘Tilt servomotor Pin RB0

‘Move only forward

for B0 = 1 to 60

pulsout 0.155 ‘Clockwise tilt, right side lift

pulsout 1, 145 ‘Left legs in place

pulsout 2, 145 ‘Right legs move forward

for B0 = 1 to 60

pulsout 0, 190 ‘Tilt counterclockwise, lift left side

pulsout 1, 200 ‘Left legs move forward

pulsout 2, 145 ‘Right legs maintain forward position

for B0 = 1 to 15

pulsout 1, 200 ‘Left legs maintain forward position

pulsout 2,145 ‘Right legs maintain forward position

for B0 = 1 to 60

pulsout 0, 172 ‘Middle position, no tilt

pulsout 1, 145 ‘Move left legs back

pulsout 2, 200 ‘Move right legs back

Not all servos respond the same way to the pulsout command. It is possible that to create a robot you will purchase servomotors, the characteristics of which will be slightly different from those that I used. In this case, please note that the parameters of the pulsout command, which determines the position of the servo motor rotor, must be adjusted. In this case, it is necessary to select numerical values pulsout parameters that would correspond to the type of servomotor used in your six-legged robot design.

This PICBASIC program allows the robot to move only in the forward direction, however, by slightly changing the program, the designer can make the robot move backward and make turns to the right and left. Installing multiple touch sensors can inform the robot about the presence of obstacles.

Servomotors

Microcontrollers 16F84

Aluminum strips

Aluminum sheet

Rods and nuts with 3 mm thread

Plastic screws, nuts and washers

Parts can be ordered from:

Walkers made from paper clips and a motor are not easy homemade toys, but also a whole arsenal of technological techniques and engineering thinking.

Making such a robot with your own hands is not only interesting, but also develops fine motor skills of the fingers, and for a child it will be a revelation - after all, a real walking robot is created out of nothing!

To assemble a simple working robot from ordinary paper clips with your own hands, you will need several simple and easily accessible materials. Firstly, these are the metal clamps themselves, as well as a small set of tools. The tools you will need are a soldering iron, solder, pliers, wire cutters, round nose pliers, and also a small Electrical engine with gearbox and battery for it.

First, you need to make a support frame from a long and thick paper clip, that is, bend it into a rectangle and securely solder its ends with solder. Parts and elements of the robot will be installed on this frame during the assembly process.

Next, you need to make loops on which the robot’s legs will be attached. They will need to be soldered to the rectangular frame using a soldering iron. Then the small legs of the walking robot are made from paper clips. In this case, it is advisable to first assemble the complex front legs, and then all the rest.

After assembling the robot's limbs, you need to start making the crankshaft. The clamp for it must be strong and absolutely even.

The crankshaft should be carefully prepared using pliers and round nose pliers. When the shaft is finished, it should be carefully placed on the motor gear. After this, special connecting rods are made that will connect the robot's legs to the crankshaft. The gear is then soldered to the crankshaft.

Then a battery and a switch are installed on the robot frame. If everything is done correctly, the robot will begin to walk.

Here is a video instruction on how to make a homemade walking robot from paper clips with your own hands, watch it if you don’t understand something from the article.

to collect the bug you will need:
- 2 small 1.5 volt motors (can be bought or removed from old toys (see photo).)
- 2 small paper clips
- 2 large paper clips

2 AAA or AA batteries

1 AAA or AA battery holder (can be purchased or removed from some toys)

1 2 cm insulation

1 wooden ball (used as a wheel) (you can use any other stabilizer, for example, removing a wheel from some old or unnecessary toy)
- 1 meter el. wires
- 2 small SPDT switches (you can buy or remove them, for example, from an old computer mouse)

and also tools:
*soldering iron + some tin
*glue gun and a glue stick for it (the glue stick can be melted simply with a soldering iron, but it is recommended to do this with a glue gun)
* wire cutters (to remove insulation)

and here are all the details

Assembly:

1. electric mode wire into 13 pieces of 6 cm each and remove the insulation from them (on both sides) 1 cm each.

2. Solder the wires to each of the components (except batteries), see the figure.

solder the wire to the batt. holder (blue)(third connection)

3. Turn the battery holder over and glue the switches to it in a “V” shape (see photo)

4. Glue 2 motors between the switches so that the chassis of the motor itself touches the ground

5. From a large paper clip and a ball we make a stabilizer (a wheel to make it easier to move along the surface)

6. connection

this is how it should all look

7. take 2 small ones. paper clips and make whiskers for a beetle out of them

8. carefully glue the mustache to the switches (use a little glue for this so as not to glue the switch itself)

9. wrap a little insulation on the running gear of the motor (for better grip)

10. Insert batteries

and you're done!)

It's not very difficult. I just did it myself!!!

The funny thing is that when he touches an obstacle with his right tendril, the other wheel stops and he turns to the left, and vice versa. (Goes around obstacles)

Microcontrollers allow, with a small number of additional parts, to control rather complex mechanisms - conveyors, automation and other modules. But in this case we are talking about a simple walking robot toy, where the entire control unit fits on a small board. This hexapod was originally conceived as as simple as possible and not requiring additional modules and blocks. The entire brain is assembled on one PIC16F887 microcontroller, powered by three cylindrical lithium-ion batteries from a laptop, TowerPro SG90 servomotors. The voltage supplied to the servo is 4.8 V (since they are powered by a voltage of 4.8-6). In the belly of the robot there are not only batteries but also an adjustable voltage stabilizer on the LD1084, which supplies 4.8 V, the microcircuit itself is installed on a small radiator, although it does not heat up much, but to be on the safe side the cooler blows on it, since there is a small one inside inner space.. The robot is controlled from a homemade remote control via a bluetooth radio channel; it can also be controlled from a computer or smartphone. The remote control is made on PIC16F873A, the bluetooth module is ready, model HC-05. The battery for the remote control was taken from mobile phone, at 4.2 V. The time spent on creating this walking robot is about 1.5 months, from idea to result.

Photo of the finished robot

Part II. Joints and ligaments.

Tell students that joints allow our limbs to bend and ligaments hold the bones of our skeleton together. How will the mobility of parts in a robot be ensured, the parts of which must freely change their position relative to each other?

Have teams find the following pins in their robotics kit boxes.

Ask students in teams to connect two beams with each pin and test the rotation of the beams relative to each other. Beams connected by which pins rotate more freely?

Make a conclusion about which pins are most suitable for movable joints.
Ask the question, what other elements from the construction set can students suggest using in places of movable joints in addition to pins?

Part III. Prototyping a robot leg.

Have each team member make a schematic drawing in their notebook for a walking robot or the part of it that is responsible for walking. When creating a diagram, have them focus only on the parts from the existing kit. Upon completion, students should discuss their schemes within their teams:

1. Are there different proposals for the type of robot movement? According to the fundamental structure of the pedipulator (pedis - leg, lat., the concept was introduced by analogy with the manipulator)?
2. What trajectory, in their opinion, is described by the extreme points of the resulting pedipulators relative to the robot?

Have students create a diagram similar to the following:

Ask to set the gear in motion through an axle and ask if the free beam attached to the gear can be considered a prototype leg? What happens if you place some surface underneath the beam? Will a robot be able to rely on such a leg? What's missing from this design?

To add additional rigidity to this “leg” design, change the mechanism to:

Note that with this design the beam no longer dangles freely - it is fixed on top, which gives it additional support. And due to the fact that the beam is now fixed in two places, its lower end now strictly describes a certain trajectory.
Add a surface again under the bottom end of the beam. What happens when the gear rotates?

Explain that we will consider this design to be the first prototype of a leg. Now it needs to be transferred to the motor.
Before doing this, ask students to identify critical points in the design, which should then be found at the motor.

If you look at the motor, it also has places for attaching parts of the pedipulator.


Students will now need to transfer the entire structure needed to create the pedipulator onto the motor. The work should be done in pairs - each pair makes a pedipulator on one motor. The end result is this:


Ask students to connect a motor to a controller and write a program on the block to move one motor for a few seconds.


The transfer of the prototype to the robot motor was a success!

After observing the system, have students draw a diagram of the mechanical system in their notebooks, along with the dimensions. If some dimensions must be calculated, then students must describe the process of calculating these quantities.