Zobrazeno 1 - 10
of 28
pro vyhledávání: '"P.A. Cowell"'
Autor:
P.A. Cowell, D.W.M Pullen
Publikováno v:
Biosystems Engineering. 94:373-386
The ability to operate at high forward speeds is vital if tractor drawn implements such as inter-row weeders and band sprayers are to be economically competitive. High-speed operation has to be accompanied with accurate positioning of the implement w
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::2662cb585f71e19fc8d5c4fba7008a2e
https://doi.org/10.1016/j.biosystemseng.2006.03.011
https://doi.org/10.1016/j.biosystemseng.2006.03.011
Autor:
D.W.M. Pullen, P.A. Cowell
Publikováno v:
Journal of Agricultural Engineering Research. 77:137-153
Accurate lateral positioning of implements operated by tractors is important in field operations such as inter-row weeding and band spraying. However, this can be difficult to achieve in practice and consequently there is much interest in automating
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::d408eebedf4f1c7689ea99e85582d203
https://doi.org/10.1006/jaer.1998.0346
https://doi.org/10.1006/jaer.1998.0346
Autor:
P.A. Cowell, D.W.M. Pullen
Publikováno v:
Journal of Agricultural Engineering Research. 67:27-34
An assessment was made of the ability of different mechanical weeding mechanisms to control weeds at different growth stages in the uncropped area between crop rows and at different forward speeds. Performance of the mechanisms was assessed in a repl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::1bda628122e3e5f5ce63ef12f7f2e2cf
https://doi.org/10.1006/jaer.1997.0148
https://doi.org/10.1006/jaer.1997.0148
Publikováno v:
Journal of Terramechanics. 31:395-414
The ability to model the ride vibration of unsuspended vehicles is at present seriously limited by lack of knowledge about the lateral and longitudinal dynamic characteristics of rolling tyres and the interaction of these characteristics with the gro
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::9f81e2da37011d179386997c3cff1c0c
https://doi.org/10.1016/0022-4898(94)90025-6
https://doi.org/10.1016/0022-4898(94)90025-6
Publikováno v:
Journal of Agricultural Engineering Research. 58:145-157
Tractor front linkages which have lateral freedom of movement are often unstable when used with ground engaging implements. If the linkage is made rigid steering becomes difficult. Front linkage-implement combinations are shown to be stable only if t
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::a380dbdf13c532af55ec39a4c99117c4
https://doi.org/10.1006/jaer.1994.1044
https://doi.org/10.1006/jaer.1994.1044
Autor:
P.A. Cowell, R.G. Thompstone
Publikováno v:
Journal of Agricultural Engineering Research. 45:175-186
Tractor front linkages pose special problems for soil engaging implements. This paper examines the effect of linkage geometry on stability in the longitudinal-vertical plane of implements supported by a depth wheel. Two unstable zones for the locatio
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::8c6e93d09586d3a4927d0f38097a95b3
https://doi.org/10.1016/s0021-8634(05)80148-9
https://doi.org/10.1016/s0021-8634(05)80148-9
Autor:
Fallak Sher Sial, P.A. Cowell
Publikováno v:
Journal of Agricultural Engineering Research. 21:313-323
The paper presents a theory for the dynamic behaviour of mouldboard ploughs in the penetration mode. In both the real and virtual hitch point cases, the equation is shown to be first order and thus to yield an exponential solution. The “time consta
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::f8d83e7b84b3c3019144c5174efc3d80
https://doi.org/10.1016/0021-8634(76)90088-3
https://doi.org/10.1016/0021-8634(76)90088-3
Autor:
P.A. Cowell, P.F. Herbert
Publikováno v:
Journal of Agricultural Engineering Research. 39:85-97
It has long been known that when long implements such as mouldboard ploughs are mounted on a tractor three-point linkage an excessive variation in working depth can occur when operating over an undulating ground profile. The principal cause of such v
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5db5f1672a657cc4544921e576d1a574
https://doi.org/10.1016/0021-8634(88)90132-1
https://doi.org/10.1016/0021-8634(88)90132-1
Autor:
P.A. Cowell, M.J. Milne
Publikováno v:
Journal of Agricultural Engineering Research. 22:353-371
The design of a hydromechanical implement control system using pure draught force sensing and modified linkage geometry is described. Draught force sensing is accomplished by summing algebraically the forces in the top and bottom mountings of the hit
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::265a5a68ce185fc9cf4b43bb1534cc6a
https://doi.org/10.1016/0021-8634(77)90067-1
https://doi.org/10.1016/0021-8634(77)90067-1
Autor:
P.A. Cowell
Publikováno v:
Journal of Agricultural Engineering Research. 14:117-125
Tractor draught control systems may be regarded as automatic regulators employing negative feedback. The problem of draught control is defined in control theory terms, in which it is shown that the implement itself forms an element in the loop. The p
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::5424d25f95eff85e5b4d9e40c92afd1c
https://doi.org/10.1016/0021-8634(69)90085-7
https://doi.org/10.1016/0021-8634(69)90085-7