Analysis Of Theo Jansen's'strandbeeste '
3.1. Theo Jansen's "Strandbeeste"
The idea for a new type of linkage came from an article in New Scientist magazine, concerning the work of Theo Jansen, a Dutch physicist / artist creating a series of kinetic sculptures, collectively named “Strandbeeste”, see Figure 3.1.1. He has constructed a wide variety of machines, all based on a similar principle. More of his creations can be seen at his web site [27] and in his book [28]. Figure 3.1.1 Strandbeeste by Theo Jansen [29]
Examination of this mechanism shows that it could provide legs that meet the design criteria. The “strandbeeste” are large enough that they could be used for transportation. They operate successfully on beaches and so have demonstrable …show more content…
They are constructed from plastic tube, said to be electrical conduit. The joining methods are not clear, but the main components appear to be lashed together with twine. It is doubtful whether this type of construction would be suitable for a working transport vehicle.
The second problem is that all legs are driven from a single central crankshaft. The rear mounted legs effectively turn in reverse relative to the front legs. However, the horizontal velocity of the foot is asymmetrical i.e. it moves faster at the beginning of the cycle than it does at the end, or vice versa. This can be seen that the velocity of the foot, for a mechanism with the same proportions that Jansen uses.
The front legs experience the profile as shown by moving from left to right between the two purple vertical lines, which indicate the foot fall and foot lift positions. The rear mounted legs will experience velocity changes in the opposite direction, that is, the velocity changes would be as indicated by moving from the right vertical line, towards the left. The feet therefore experience longitudinal movements in relation to each other as the machine walks, and they cannot remain firmly planted on the ground. At least one foot must move to accommodate the pull exerted by the …show more content…
For small prototype, rivet joint is sufficient for smooth action. But for big bodies, bearings must be employed to reduce frictional losses.
3.3. Advantages of Theo Jansen mechanism
The Jansen mechanism is worth pursuing as a valid alternative mechanism for use as a leg for a walking machine. Although it is the only leg design assessed in this way, the only other design contender worth.
No. Criterion Discussion
1 Static balance The static balance is not affected by the leg design itself, and a six or eight legged walker could be designed with this leg type. Quadrupeds cannot be achieved, as the best duty cycle found was 67%
2 Active propulsion It would be simple to power all legs on a walker with this leg mechanism.
3 Minimal power consumption As the Jansen mechanism is a linkage with stiff links, and single actuation, it will not require much energy to turn. The main obstacle would be friction, and this can be minimized with suitable detail
The idea for a new type of linkage came from an article in New Scientist magazine, concerning the work of Theo Jansen, a Dutch physicist / artist creating a series of kinetic sculptures, collectively named “Strandbeeste”, see Figure 3.1.1. He has constructed a wide variety of machines, all based on a similar principle. More of his creations can be seen at his web site [27] and in his book [28]. Figure 3.1.1 Strandbeeste by Theo Jansen [29]
Examination of this mechanism shows that it could provide legs that meet the design criteria. The “strandbeeste” are large enough that they could be used for transportation. They operate successfully on beaches and so have demonstrable …show more content…
They are constructed from plastic tube, said to be electrical conduit. The joining methods are not clear, but the main components appear to be lashed together with twine. It is doubtful whether this type of construction would be suitable for a working transport vehicle.
The second problem is that all legs are driven from a single central crankshaft. The rear mounted legs effectively turn in reverse relative to the front legs. However, the horizontal velocity of the foot is asymmetrical i.e. it moves faster at the beginning of the cycle than it does at the end, or vice versa. This can be seen that the velocity of the foot, for a mechanism with the same proportions that Jansen uses.
The front legs experience the profile as shown by moving from left to right between the two purple vertical lines, which indicate the foot fall and foot lift positions. The rear mounted legs will experience velocity changes in the opposite direction, that is, the velocity changes would be as indicated by moving from the right vertical line, towards the left. The feet therefore experience longitudinal movements in relation to each other as the machine walks, and they cannot remain firmly planted on the ground. At least one foot must move to accommodate the pull exerted by the …show more content…
For small prototype, rivet joint is sufficient for smooth action. But for big bodies, bearings must be employed to reduce frictional losses.
3.3. Advantages of Theo Jansen mechanism
The Jansen mechanism is worth pursuing as a valid alternative mechanism for use as a leg for a walking machine. Although it is the only leg design assessed in this way, the only other design contender worth.
No. Criterion Discussion
1 Static balance The static balance is not affected by the leg design itself, and a six or eight legged walker could be designed with this leg type. Quadrupeds cannot be achieved, as the best duty cycle found was 67%
2 Active propulsion It would be simple to power all legs on a walker with this leg mechanism.
3 Minimal power consumption As the Jansen mechanism is a linkage with stiff links, and single actuation, it will not require much energy to turn. The main obstacle would be friction, and this can be minimized with suitable detail