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efficiency of the system, making it impractical when traveling over greater distances, much
larger dimensions, both occupied space in the vehicle and a large weight. The track system
significantly hampers autonomous steering when performing a turn maneuver due to slippage. This type of drive significantly degrades the ground on which it moves, so it cannot be
used in some tasks, for example patrolling farmlands or forests.
The walking drives solve the problem of overcoming obstacles. With a properly designed
structure, the platform can enter the obstacle, raising the leg accordingly. The problem with
moving on loose ground is solved by proper foot structure and control algorithm that minimizes the longitudinal force between the foot and the ground. Consumption of materials in
contact with the ground is also significantly reduced. It results from a larger contact surface than in the case of wheels, different characteristic of the distribution of contact forces
between the vehicle and the ground. The risk of damage to the surface is also reduced. In the
case of a walking system it is also possible to choose the place where the foot is applied to
the ground, with less risk of damage to the foot or to control of grip before transferring the
entire load to the foot. The cost of transport is larger than for wheels but smaller than in a
tracked drive. For example, energy efficient DURUS robot has 1,5 COT (cost of transport),
Boston Dynamics ATLAS ca. 20 COT, Boston Dynamic Cheetah 0,5 COT, a car 0,05–0,25
COT, tracked vehicle like BWP-1 has 3,5 COT, Leopard 2 A4 6,5 COT. For comparison
human during walk has 0,2 COT.
The walking drives also have disadvantages. Currently the biggest problem is maintaining balance, especially when moving on uneven terrain. Currently, a strong emphasis is put
on developing control algorithms that allow moving vehicles in difficult conditions, which
makes them very complex. For this purpose, leg mechanisms with several degrees of freedom
are being developed. In addition, feet with two, sometimes three, active degrees of freedom
are used. Most often, the drives are mounted in the legs, making them heavy, expensive and
additionally sensitive to damage. In order to increase the efficiency of the drive, the weight of
the legs is minimized by slimming the supporting structure, which simultaneously increases
the susceptibility to damage or is made of lighter materials, which in turn increases the cost
of the construction.
2.2 Proposed solution
The use of the Klann mechanism allows to eliminate some problems of anthropomorphic
drives. Stabilization is achieved by the use of eight legs. Thanks to that, the robot has four
foot on the ground all the time. In the basic version, all legs are powered by two motors. This
significantly reduces the cost of the robot’s limb. In addition, motors are placed in the body,
which significantly reduces the weight of the limbs, which consist only of construction elements and susceptibility to mechanical damage. In the case of damage, replacement of the
leg is much cheaper, because sensitive elements such as motors, sensors, control electronics or
power and control wires are placed in the body. The disadvantage is the number of required
legs for the mechanism to work properly. Because of this, the inertia of the mechanism is
quite large, but it is evenly distributed, reducing the amplitude of load torque on the motor.
When the platform moves at a constant speed, the motor also rotates in one direction at
a constant speed. Because the walking trajectory is predetermined by the geometry of the
mechanism, with varying terrain, the efficiency of movement is lower than in the case of
mechanisms with more degrees of freedom. The clan mechanism is a plane mechanism, so
when the platform turns, there are large slides on feet, just like in a track drive. The stability
of the vehicle is not affected, however, they cause major disturbances in odometry systems.
These slides are necessary for the proper execution of the turn maneuver and result from
the construction of the mechanism. For this reason, when the platform moves on a surface
with high adhesion, large lateral forces are created in the limbs, which impede movement and
additionally burden the structure. With a loose or low-adhesion surface like a solid rock, this
should not be a problem.
The Klann linkage mechanism in 1994 was developed, as an analogy to animal limbs.
An implementation of a gait motion, as a replacement for wheel vehicle drive, was the goal
efficiency of the system, making it impractical when traveling over greater distances, much
larger dimensions, both occupied space in the vehicle and a large weight. The track system
significantly hampers autonomous steering when performing a turn maneuver due to slippage. This type of drive significantly degrades the ground on which it moves, so it cannot be
used in some tasks, for example patrolling farmlands or forests.
The walking drives solve the problem of overcoming obstacles. With a properly designed
structure, the platform can enter the obstacle, raising the leg accordingly. The problem with
moving on loose ground is solved by proper foot structure and control algorithm that minimizes the longitudinal force between the foot and the ground. Consumption of materials in
contact with the ground is also significantly reduced. It results from a larger contact surface than in the case of wheels, different characteristic of the distribution of contact forces
between the vehicle and the ground. The risk of damage to the surface is also reduced. In the
case of a walking system it is also possible to choose the place where the foot is applied to
the ground, with less risk of damage to the foot or to control of grip before transferring the
entire load to the foot. The cost of transport is larger than for wheels but smaller than in a
tracked drive. For example, energy efficient DURUS robot has 1,5 COT (cost of transport),
Boston Dynamics ATLAS ca. 20 COT, Boston Dynamic Cheetah 0,5 COT, a car 0,05–0,25
COT, tracked vehicle like BWP-1 has 3,5 COT, Leopard 2 A4 6,5 COT. For comparison
human during walk has 0,2 COT.
The walking drives also have disadvantages. Currently the biggest problem is maintaining balance, especially when moving on uneven terrain. Currently, a strong emphasis is put
on developing control algorithms that allow moving vehicles in difficult conditions, which
makes them very complex. For this purpose, leg mechanisms with several degrees of freedom
are being developed. In addition, feet with two, sometimes three, active degrees of freedom
are used. Most often, the drives are mounted in the legs, making them heavy, expensive and
additionally sensitive to damage. In order to increase the efficiency of the drive, the weight of
the legs is minimized by slimming the supporting structure, which simultaneously increases
the susceptibility to damage or is made of lighter materials, which in turn increases the cost
of the construction.
2.2 Proposed solution
The use of the Klann mechanism allows to eliminate some problems of anthropomorphic
drives. Stabilization is achieved by the use of eight legs. Thanks to that, the robot has four
foot on the ground all the time. In the basic version, all legs are powered by two motors. This
significantly reduces the cost of the robot’s limb. In addition, motors are placed in the body,
which significantly reduces the weight of the limbs, which consist only of construction elements and susceptibility to mechanical damage. In the case of damage, replacement of the
leg is much cheaper, because sensitive elements such as motors, sensors, control electronics or
power and control wires are placed in the body. The disadvantage is the number of required
legs for the mechanism to work properly. Because of this, the inertia of the mechanism is
quite large, but it is evenly distributed, reducing the amplitude of load torque on the motor.
When the platform moves at a constant speed, the motor also rotates in one direction at
a constant speed. Because the walking trajectory is predetermined by the geometry of the
mechanism, with varying terrain, the efficiency of movement is lower than in the case of
mechanisms with more degrees of freedom. The clan mechanism is a plane mechanism, so
when the platform turns, there are large slides on feet, just like in a track drive. The stability
of the vehicle is not affected, however, they cause major disturbances in odometry systems.
These slides are necessary for the proper execution of the turn maneuver and result from
the construction of the mechanism. For this reason, when the platform moves on a surface
with high adhesion, large lateral forces are created in the limbs, which impede movement and
additionally burden the structure. With a loose or low-adhesion surface like a solid rock, this
should not be a problem.
The Klann linkage mechanism in 1994 was developed, as an analogy to animal limbs.
An implementation of a gait motion, as a replacement for wheel vehicle drive, was the goal